Patchwork [v2,6/8] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5

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Submitter Mika Westerberg
Date July 4, 2013, 8:58 a.m.
Message ID <20130704085844.GF4898@intel.com>
Download mbox | patch
Permalink /patch/256821/
State Not Applicable
Headers show

Comments

Mika Westerberg - July 4, 2013, 8:58 a.m.
On Wed, Jul 03, 2013 at 11:40:42PM +0200, Rafael J. Wysocki wrote:
> On Wednesday, July 03, 2013 05:04:53 PM Mika Westerberg wrote:
> > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> > 
> > Correct ACPI PCI hotplug imeplementation should have _RMV method in a
> > PCI slot (device under pci bridge). In Acer Aspire S5 case we have it
> > deeper in hierarchy:
> > 
> > Device (RP05)
> > {
> >    // ...
> >    Device (HRUP)
> >    {
> >        // ...
> >        Device (HRDN)
> >        {
> >            // ...
> >            Device (EPUP)
> >            {
> >                // ...
> >                Method (_RMV, 0, NotSerialized)  // _RMV: Removal Status
> >                {
> >                    Return (One)
> >                }
> >            }
> >        }
> >    }
> > }
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> >  drivers/pci/hotplug/acpi_pcihp.c | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> > 
> > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > index 2a47e82..d92ebfb 100644
> > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > @@ -422,6 +422,19 @@ static int pcihp_is_ejectable(acpi_handle handle)
> >  	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> >  	if (ACPI_SUCCESS(status) && removable)
> >  		return 1;
> > +
> > +	/*
> > +	 * Workaround for Thunderbolt implementation on Acer Aspire S5.
> > +	 *
> > +	 * Correct ACPI PCI hotplug imeplementation has _RMV method in a PCI
> > +	 * slot (device under pci bridge). In Acer Aspire S5 case we have it
> > +	 * deeper in hierarchy.
> > +	 */
> > +	status = acpi_evaluate_integer(handle, "HRDN.EPUP._RMV", NULL,
> > +			&removable);
> 
> Well, calling stuff like this directly from a general function is kind of ugly.
> 
> Can we use something like a quirk instead?  A DMI check or something?

Sure we can. How about something like the patch below?

From: Mika Westerberg <mika.westerberg@linux.intel.com>
Subject: [PATCH] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5

The acpiphp driver finds out whether the device is removable by checking
whether it has _RMV method directly behind it (and if it returns 1).
However, at least on Acer Aspire S5 with Thunderbolt host router has this
method placed behind a device called EPUP (endpoint upstream port?) and not
in the usual place expected by the acpiphp driver. The ASL code below shows
how this is done on that machine:

Device (RP05)
{
	...
	Device (HRUP)
	{
		Name (_ADR, Zero)
		Name (_PRW, Package (0x02)
		{
			0x09,
			0x04
		})
		Device (HRDN)
		{
			Name (_ADR, 0x00040000)
			Name (_PRW, Package (0x02)
			{
				0x09,
				0x04
			})
			Device (EPUP)
			{
				Name (_ADR, Zero)
				Method (_RMV, 0, NotSerialized)
				{
					Return (One)
				}
			}
		}
	}
	...

Fix this by adding a DMI quirk for the Acer Aspire S5 machine that gives an
alternative path to the _RMV method.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/hotplug/acpi_pcihp.c | 57 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 5 deletions(-)
Rafael J. Wysocki - July 4, 2013, 12:36 p.m.
On Thursday, July 04, 2013 11:58:44 AM Mika Westerberg wrote:
> On Wed, Jul 03, 2013 at 11:40:42PM +0200, Rafael J. Wysocki wrote:
> > On Wednesday, July 03, 2013 05:04:53 PM Mika Westerberg wrote:
> > > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> > > 
> > > Correct ACPI PCI hotplug imeplementation should have _RMV method in a
> > > PCI slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > deeper in hierarchy:
> > > 
> > > Device (RP05)
> > > {
> > >    // ...
> > >    Device (HRUP)
> > >    {
> > >        // ...
> > >        Device (HRDN)
> > >        {
> > >            // ...
> > >            Device (EPUP)
> > >            {
> > >                // ...
> > >                Method (_RMV, 0, NotSerialized)  // _RMV: Removal Status
> > >                {
> > >                    Return (One)
> > >                }
> > >            }
> > >        }
> > >    }
> > > }
> > > 
> > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > ---
> > >  drivers/pci/hotplug/acpi_pcihp.c | 13 +++++++++++++
> > >  1 file changed, 13 insertions(+)
> > > 
> > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > index 2a47e82..d92ebfb 100644
> > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > @@ -422,6 +422,19 @@ static int pcihp_is_ejectable(acpi_handle handle)
> > >  	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > >  	if (ACPI_SUCCESS(status) && removable)
> > >  		return 1;
> > > +
> > > +	/*
> > > +	 * Workaround for Thunderbolt implementation on Acer Aspire S5.
> > > +	 *
> > > +	 * Correct ACPI PCI hotplug imeplementation has _RMV method in a PCI
> > > +	 * slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > +	 * deeper in hierarchy.
> > > +	 */
> > > +	status = acpi_evaluate_integer(handle, "HRDN.EPUP._RMV", NULL,
> > > +			&removable);
> > 
> > Well, calling stuff like this directly from a general function is kind of ugly.
> > 
> > Can we use something like a quirk instead?  A DMI check or something?
> 
> Sure we can. How about something like the patch below?

Well, it goes into the right (to me) direction. :-)

Some comments below.

> From: Mika Westerberg <mika.westerberg@linux.intel.com>
> Subject: [PATCH] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5
> 
> The acpiphp driver finds out whether the device is removable by checking
> whether it has _RMV method directly behind it (and if it returns 1).
> However, at least on Acer Aspire S5 with Thunderbolt host router has this
> method placed behind a device called EPUP (endpoint upstream port?) and not
> in the usual place expected by the acpiphp driver. The ASL code below shows
> how this is done on that machine:
> 
> Device (RP05)
> {
> 	...
> 	Device (HRUP)
> 	{
> 		Name (_ADR, Zero)
> 		Name (_PRW, Package (0x02)
> 		{
> 			0x09,
> 			0x04
> 		})
> 		Device (HRDN)
> 		{
> 			Name (_ADR, 0x00040000)
> 			Name (_PRW, Package (0x02)
> 			{
> 				0x09,
> 				0x04
> 			})
> 			Device (EPUP)
> 			{
> 				Name (_ADR, Zero)
> 				Method (_RMV, 0, NotSerialized)
> 				{
> 					Return (One)
> 				}
> 			}
> 		}
> 	}
> 	...
> 
> Fix this by adding a DMI quirk for the Acer Aspire S5 machine that gives an
> alternative path to the _RMV method.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
>  drivers/pci/hotplug/acpi_pcihp.c | 57 ++++++++++++++++++++++++++++++++++++----
>  1 file changed, 52 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> index 2a47e82..99fccf3 100644
> --- a/drivers/pci/hotplug/acpi_pcihp.c
> +++ b/drivers/pci/hotplug/acpi_pcihp.c
> @@ -33,6 +33,7 @@
>  #include <linux/acpi.h>
>  #include <linux/pci-acpi.h>
>  #include <linux/slab.h>
> +#include <linux/dmi.h>
>  
>  #define MY_NAME	"acpi_pcihp"
>  
> @@ -408,21 +409,67 @@ got_one:
>  }
>  EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
>  
> +/**
> + * pcihp_is_removable - is the given ACPI device removable
> + * @handle: ACPI handle of the device
> + *
> + * Try to find out whether the given ACPI device is removable by evaluating
> + * its _RMV and returning the result. If we can't find the _RMV directly
> + * under the device use system specific quirks to locate it.
> + */
> +static bool pcihp_is_removable(acpi_handle handle)
> +{

People are generally used to seeing DMI lists outside of functions.

> +	static const struct dmi_system_id rmv_paths[] = {
> +		{
> +			/*
> +			 * On Acer Aspire S5 the _RMV method for the
> +			 * Thunderbolt host router upstream port is not
> +			 * located directly under the device but it is
> +			 * instead placed a bit deeper in the hierarchy.
> +			 */
> +			.ident = "Acer Aspire S5",
> +			.matches = {
> +				DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> +				DMI_MATCH(DMI_PRODUCT_NAME, "Aspire S5-391"),
> +			},
> +			.driver_data = "HRDN.EPUP._RMV",

Use .callback instead? ->

> +		},
> +		{ }
> +	};
> +	const struct dmi_system_id *id;
> +	unsigned long long removable;
> +	acpi_status status;
> +
> +	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> +	if (ACPI_SUCCESS(status))
> +		return !!removable;
> +
> +	/* Try system specific quirks */
> +	id = dmi_first_match(rmv_paths);
> +	if (id && id->driver_data) {

-> And here do

	if (id && id->callback)
		return id->callback(id);

> +		char path[64];
> +
> +		strlcpy(path, id->driver_data, sizeof(path));
> +		status = acpi_evaluate_integer(handle, path, NULL, &removable);
> +		if (ACPI_SUCCESS(status))
> +			return !!removable;
> +	}
> +
> +	return false;
> +}
> +
>  static int pcihp_is_ejectable(acpi_handle handle)
>  {
>  	acpi_status status;
>  	acpi_handle tmp;
> -	unsigned long long removable;
> +
>  	status = acpi_get_handle(handle, "_ADR", &tmp);
>  	if (ACPI_FAILURE(status))
>  		return 0;
>  	status = acpi_get_handle(handle, "_EJ0", &tmp);
>  	if (ACPI_SUCCESS(status))
>  		return 1;
> -	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> -	if (ACPI_SUCCESS(status) && removable)
> -		return 1;

I'd keep the above unchanged and simply add a "platform check" function.

> -	return 0;
> +	return pcihp_is_removable(handle);
>  }
>  
>  /**

Thanks,
Rafael
Mika Westerberg - July 4, 2013, 12:53 p.m.
On Thu, Jul 04, 2013 at 02:36:00PM +0200, Rafael J. Wysocki wrote:
> On Thursday, July 04, 2013 11:58:44 AM Mika Westerberg wrote:
> > On Wed, Jul 03, 2013 at 11:40:42PM +0200, Rafael J. Wysocki wrote:
> > > On Wednesday, July 03, 2013 05:04:53 PM Mika Westerberg wrote:
> > > > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> > > > 
> > > > Correct ACPI PCI hotplug imeplementation should have _RMV method in a
> > > > PCI slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > deeper in hierarchy:
> > > > 
> > > > Device (RP05)
> > > > {
> > > >    // ...
> > > >    Device (HRUP)
> > > >    {
> > > >        // ...
> > > >        Device (HRDN)
> > > >        {
> > > >            // ...
> > > >            Device (EPUP)
> > > >            {
> > > >                // ...
> > > >                Method (_RMV, 0, NotSerialized)  // _RMV: Removal Status
> > > >                {
> > > >                    Return (One)
> > > >                }
> > > >            }
> > > >        }
> > > >    }
> > > > }
> > > > 
> > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > ---
> > > >  drivers/pci/hotplug/acpi_pcihp.c | 13 +++++++++++++
> > > >  1 file changed, 13 insertions(+)
> > > > 
> > > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > > index 2a47e82..d92ebfb 100644
> > > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > > @@ -422,6 +422,19 @@ static int pcihp_is_ejectable(acpi_handle handle)
> > > >  	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > > >  	if (ACPI_SUCCESS(status) && removable)
> > > >  		return 1;
> > > > +
> > > > +	/*
> > > > +	 * Workaround for Thunderbolt implementation on Acer Aspire S5.
> > > > +	 *
> > > > +	 * Correct ACPI PCI hotplug imeplementation has _RMV method in a PCI
> > > > +	 * slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > +	 * deeper in hierarchy.
> > > > +	 */
> > > > +	status = acpi_evaluate_integer(handle, "HRDN.EPUP._RMV", NULL,
> > > > +			&removable);
> > > 
> > > Well, calling stuff like this directly from a general function is kind of ugly.
> > > 
> > > Can we use something like a quirk instead?  A DMI check or something?
> > 
> > Sure we can. How about something like the patch below?
> 
> Well, it goes into the right (to me) direction. :-)
> 
> Some comments below.
> 
> > From: Mika Westerberg <mika.westerberg@linux.intel.com>
> > Subject: [PATCH] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5
> > 
> > The acpiphp driver finds out whether the device is removable by checking
> > whether it has _RMV method directly behind it (and if it returns 1).
> > However, at least on Acer Aspire S5 with Thunderbolt host router has this
> > method placed behind a device called EPUP (endpoint upstream port?) and not
> > in the usual place expected by the acpiphp driver. The ASL code below shows
> > how this is done on that machine:
> > 
> > Device (RP05)
> > {
> > 	...
> > 	Device (HRUP)
> > 	{
> > 		Name (_ADR, Zero)
> > 		Name (_PRW, Package (0x02)
> > 		{
> > 			0x09,
> > 			0x04
> > 		})
> > 		Device (HRDN)
> > 		{
> > 			Name (_ADR, 0x00040000)
> > 			Name (_PRW, Package (0x02)
> > 			{
> > 				0x09,
> > 				0x04
> > 			})
> > 			Device (EPUP)
> > 			{
> > 				Name (_ADR, Zero)
> > 				Method (_RMV, 0, NotSerialized)
> > 				{
> > 					Return (One)
> > 				}
> > 			}
> > 		}
> > 	}
> > 	...
> > 
> > Fix this by adding a DMI quirk for the Acer Aspire S5 machine that gives an
> > alternative path to the _RMV method.
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> >  drivers/pci/hotplug/acpi_pcihp.c | 57 ++++++++++++++++++++++++++++++++++++----
> >  1 file changed, 52 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > index 2a47e82..99fccf3 100644
> > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > @@ -33,6 +33,7 @@
> >  #include <linux/acpi.h>
> >  #include <linux/pci-acpi.h>
> >  #include <linux/slab.h>
> > +#include <linux/dmi.h>
> >  
> >  #define MY_NAME	"acpi_pcihp"
> >  
> > @@ -408,21 +409,67 @@ got_one:
> >  }
> >  EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
> >  
> > +/**
> > + * pcihp_is_removable - is the given ACPI device removable
> > + * @handle: ACPI handle of the device
> > + *
> > + * Try to find out whether the given ACPI device is removable by evaluating
> > + * its _RMV and returning the result. If we can't find the _RMV directly
> > + * under the device use system specific quirks to locate it.
> > + */
> > +static bool pcihp_is_removable(acpi_handle handle)
> > +{
> 
> People are generally used to seeing DMI lists outside of functions.

OK.

> > +	static const struct dmi_system_id rmv_paths[] = {
> > +		{
> > +			/*
> > +			 * On Acer Aspire S5 the _RMV method for the
> > +			 * Thunderbolt host router upstream port is not
> > +			 * located directly under the device but it is
> > +			 * instead placed a bit deeper in the hierarchy.
> > +			 */
> > +			.ident = "Acer Aspire S5",
> > +			.matches = {
> > +				DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> > +				DMI_MATCH(DMI_PRODUCT_NAME, "Aspire S5-391"),
> > +			},
> > +			.driver_data = "HRDN.EPUP._RMV",
> 
> Use .callback instead? ->
> 
> > +		},
> > +		{ }
> > +	};
> > +	const struct dmi_system_id *id;
> > +	unsigned long long removable;
> > +	acpi_status status;
> > +
> > +	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > +	if (ACPI_SUCCESS(status))
> > +		return !!removable;
> > +
> > +	/* Try system specific quirks */
> > +	id = dmi_first_match(rmv_paths);
> > +	if (id && id->driver_data) {
> 
> -> And here do
> 
> 	if (id && id->callback)
> 		return id->callback(id);

There is a problem with the above that we can't pass an ACPI handle to the
callback function.

> 
> > +		char path[64];
> > +
> > +		strlcpy(path, id->driver_data, sizeof(path));
> > +		status = acpi_evaluate_integer(handle, path, NULL, &removable);
> > +		if (ACPI_SUCCESS(status))
> > +			return !!removable;
> > +	}
> > +
> > +	return false;
> > +}
> > +
> >  static int pcihp_is_ejectable(acpi_handle handle)
> >  {
> >  	acpi_status status;
> >  	acpi_handle tmp;
> > -	unsigned long long removable;
> > +
> >  	status = acpi_get_handle(handle, "_ADR", &tmp);
> >  	if (ACPI_FAILURE(status))
> >  		return 0;
> >  	status = acpi_get_handle(handle, "_EJ0", &tmp);
> >  	if (ACPI_SUCCESS(status))
> >  		return 1;
> > -	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > -	if (ACPI_SUCCESS(status) && removable)
> > -		return 1;
> 
> I'd keep the above unchanged and simply add a "platform check" function.

OK, thanks.
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Rafael J. Wysocki - July 4, 2013, 1:14 p.m.
On Thursday, July 04, 2013 03:53:38 PM Mika Westerberg wrote:
> On Thu, Jul 04, 2013 at 02:36:00PM +0200, Rafael J. Wysocki wrote:
> > On Thursday, July 04, 2013 11:58:44 AM Mika Westerberg wrote:
> > > On Wed, Jul 03, 2013 at 11:40:42PM +0200, Rafael J. Wysocki wrote:
> > > > On Wednesday, July 03, 2013 05:04:53 PM Mika Westerberg wrote:
> > > > > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> > > > > 
> > > > > Correct ACPI PCI hotplug imeplementation should have _RMV method in a
> > > > > PCI slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > > deeper in hierarchy:
> > > > > 
> > > > > Device (RP05)
> > > > > {
> > > > >    // ...
> > > > >    Device (HRUP)
> > > > >    {
> > > > >        // ...
> > > > >        Device (HRDN)
> > > > >        {
> > > > >            // ...
> > > > >            Device (EPUP)
> > > > >            {
> > > > >                // ...
> > > > >                Method (_RMV, 0, NotSerialized)  // _RMV: Removal Status
> > > > >                {
> > > > >                    Return (One)
> > > > >                }
> > > > >            }
> > > > >        }
> > > > >    }
> > > > > }
> > > > > 
> > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > ---
> > > > >  drivers/pci/hotplug/acpi_pcihp.c | 13 +++++++++++++
> > > > >  1 file changed, 13 insertions(+)
> > > > > 
> > > > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > index 2a47e82..d92ebfb 100644
> > > > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > @@ -422,6 +422,19 @@ static int pcihp_is_ejectable(acpi_handle handle)
> > > > >  	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > > > >  	if (ACPI_SUCCESS(status) && removable)
> > > > >  		return 1;
> > > > > +
> > > > > +	/*
> > > > > +	 * Workaround for Thunderbolt implementation on Acer Aspire S5.
> > > > > +	 *
> > > > > +	 * Correct ACPI PCI hotplug imeplementation has _RMV method in a PCI
> > > > > +	 * slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > > +	 * deeper in hierarchy.
> > > > > +	 */
> > > > > +	status = acpi_evaluate_integer(handle, "HRDN.EPUP._RMV", NULL,
> > > > > +			&removable);
> > > > 
> > > > Well, calling stuff like this directly from a general function is kind of ugly.
> > > > 
> > > > Can we use something like a quirk instead?  A DMI check or something?
> > > 
> > > Sure we can. How about something like the patch below?
> > 
> > Well, it goes into the right (to me) direction. :-)
> > 
> > Some comments below.
> > 
> > > From: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > Subject: [PATCH] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5
> > > 
> > > The acpiphp driver finds out whether the device is removable by checking
> > > whether it has _RMV method directly behind it (and if it returns 1).
> > > However, at least on Acer Aspire S5 with Thunderbolt host router has this
> > > method placed behind a device called EPUP (endpoint upstream port?) and not
> > > in the usual place expected by the acpiphp driver. The ASL code below shows
> > > how this is done on that machine:
> > > 
> > > Device (RP05)
> > > {
> > > 	...
> > > 	Device (HRUP)
> > > 	{
> > > 		Name (_ADR, Zero)
> > > 		Name (_PRW, Package (0x02)
> > > 		{
> > > 			0x09,
> > > 			0x04
> > > 		})
> > > 		Device (HRDN)
> > > 		{
> > > 			Name (_ADR, 0x00040000)
> > > 			Name (_PRW, Package (0x02)
> > > 			{
> > > 				0x09,
> > > 				0x04
> > > 			})
> > > 			Device (EPUP)
> > > 			{
> > > 				Name (_ADR, Zero)
> > > 				Method (_RMV, 0, NotSerialized)
> > > 				{
> > > 					Return (One)
> > > 				}
> > > 			}
> > > 		}
> > > 	}
> > > 	...
> > > 
> > > Fix this by adding a DMI quirk for the Acer Aspire S5 machine that gives an
> > > alternative path to the _RMV method.
> > > 
> > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > ---
> > >  drivers/pci/hotplug/acpi_pcihp.c | 57 ++++++++++++++++++++++++++++++++++++----
> > >  1 file changed, 52 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > index 2a47e82..99fccf3 100644
> > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > @@ -33,6 +33,7 @@
> > >  #include <linux/acpi.h>
> > >  #include <linux/pci-acpi.h>
> > >  #include <linux/slab.h>
> > > +#include <linux/dmi.h>
> > >  
> > >  #define MY_NAME	"acpi_pcihp"
> > >  
> > > @@ -408,21 +409,67 @@ got_one:
> > >  }
> > >  EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
> > >  
> > > +/**
> > > + * pcihp_is_removable - is the given ACPI device removable
> > > + * @handle: ACPI handle of the device
> > > + *
> > > + * Try to find out whether the given ACPI device is removable by evaluating
> > > + * its _RMV and returning the result. If we can't find the _RMV directly
> > > + * under the device use system specific quirks to locate it.
> > > + */
> > > +static bool pcihp_is_removable(acpi_handle handle)
> > > +{
> > 
> > People are generally used to seeing DMI lists outside of functions.
> 
> OK.
> 
> > > +	static const struct dmi_system_id rmv_paths[] = {
> > > +		{
> > > +			/*
> > > +			 * On Acer Aspire S5 the _RMV method for the
> > > +			 * Thunderbolt host router upstream port is not
> > > +			 * located directly under the device but it is
> > > +			 * instead placed a bit deeper in the hierarchy.
> > > +			 */
> > > +			.ident = "Acer Aspire S5",
> > > +			.matches = {
> > > +				DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> > > +				DMI_MATCH(DMI_PRODUCT_NAME, "Aspire S5-391"),
> > > +			},
> > > +			.driver_data = "HRDN.EPUP._RMV",
> > 
> > Use .callback instead? ->
> > 
> > > +		},
> > > +		{ }
> > > +	};
> > > +	const struct dmi_system_id *id;
> > > +	unsigned long long removable;
> > > +	acpi_status status;
> > > +
> > > +	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > > +	if (ACPI_SUCCESS(status))
> > > +		return !!removable;
> > > +
> > > +	/* Try system specific quirks */
> > > +	id = dmi_first_match(rmv_paths);
> > > +	if (id && id->driver_data) {
> > 
> > -> And here do
> > 
> > 	if (id && id->callback)
> > 		return id->callback(id);
> 
> There is a problem with the above that we can't pass an ACPI handle to the
> callback function.

Ah, right.

Well, you can do

	if (id && id->driver_data) {
		bool (*callback)(acpi_handle) = id->driver_data;

		return callback(handle);
	}

although it's a bit hackish.

> > 
> > > +		char path[64];
> > > +
> > > +		strlcpy(path, id->driver_data, sizeof(path));

BTW, why didn't you want to pass id->driver_data directly here?

> > > +		status = acpi_evaluate_integer(handle, path, NULL, &removable);
> > > +		if (ACPI_SUCCESS(status))
> > > +			return !!removable;
> > > +	}
> > > +
> > > +	return false;
> > > +}
> > > +

Thanks,
Rafael
Mika Westerberg - July 4, 2013, 1:33 p.m.
On Thu, Jul 04, 2013 at 03:14:58PM +0200, Rafael J. Wysocki wrote:
> On Thursday, July 04, 2013 03:53:38 PM Mika Westerberg wrote:
> > On Thu, Jul 04, 2013 at 02:36:00PM +0200, Rafael J. Wysocki wrote:
> > > On Thursday, July 04, 2013 11:58:44 AM Mika Westerberg wrote:
> > > > On Wed, Jul 03, 2013 at 11:40:42PM +0200, Rafael J. Wysocki wrote:
> > > > > On Wednesday, July 03, 2013 05:04:53 PM Mika Westerberg wrote:
> > > > > > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> > > > > > 
> > > > > > Correct ACPI PCI hotplug imeplementation should have _RMV method in a
> > > > > > PCI slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > > > deeper in hierarchy:
> > > > > > 
> > > > > > Device (RP05)
> > > > > > {
> > > > > >    // ...
> > > > > >    Device (HRUP)
> > > > > >    {
> > > > > >        // ...
> > > > > >        Device (HRDN)
> > > > > >        {
> > > > > >            // ...
> > > > > >            Device (EPUP)
> > > > > >            {
> > > > > >                // ...
> > > > > >                Method (_RMV, 0, NotSerialized)  // _RMV: Removal Status
> > > > > >                {
> > > > > >                    Return (One)
> > > > > >                }
> > > > > >            }
> > > > > >        }
> > > > > >    }
> > > > > > }
> > > > > > 
> > > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > > ---
> > > > > >  drivers/pci/hotplug/acpi_pcihp.c | 13 +++++++++++++
> > > > > >  1 file changed, 13 insertions(+)
> > > > > > 
> > > > > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > > index 2a47e82..d92ebfb 100644
> > > > > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > > > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > > @@ -422,6 +422,19 @@ static int pcihp_is_ejectable(acpi_handle handle)
> > > > > >  	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > > > > >  	if (ACPI_SUCCESS(status) && removable)
> > > > > >  		return 1;
> > > > > > +
> > > > > > +	/*
> > > > > > +	 * Workaround for Thunderbolt implementation on Acer Aspire S5.
> > > > > > +	 *
> > > > > > +	 * Correct ACPI PCI hotplug imeplementation has _RMV method in a PCI
> > > > > > +	 * slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > > > +	 * deeper in hierarchy.
> > > > > > +	 */
> > > > > > +	status = acpi_evaluate_integer(handle, "HRDN.EPUP._RMV", NULL,
> > > > > > +			&removable);
> > > > > 
> > > > > Well, calling stuff like this directly from a general function is kind of ugly.
> > > > > 
> > > > > Can we use something like a quirk instead?  A DMI check or something?
> > > > 
> > > > Sure we can. How about something like the patch below?
> > > 
> > > Well, it goes into the right (to me) direction. :-)
> > > 
> > > Some comments below.
> > > 
> > > > From: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > Subject: [PATCH] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5
> > > > 
> > > > The acpiphp driver finds out whether the device is removable by checking
> > > > whether it has _RMV method directly behind it (and if it returns 1).
> > > > However, at least on Acer Aspire S5 with Thunderbolt host router has this
> > > > method placed behind a device called EPUP (endpoint upstream port?) and not
> > > > in the usual place expected by the acpiphp driver. The ASL code below shows
> > > > how this is done on that machine:
> > > > 
> > > > Device (RP05)
> > > > {
> > > > 	...
> > > > 	Device (HRUP)
> > > > 	{
> > > > 		Name (_ADR, Zero)
> > > > 		Name (_PRW, Package (0x02)
> > > > 		{
> > > > 			0x09,
> > > > 			0x04
> > > > 		})
> > > > 		Device (HRDN)
> > > > 		{
> > > > 			Name (_ADR, 0x00040000)
> > > > 			Name (_PRW, Package (0x02)
> > > > 			{
> > > > 				0x09,
> > > > 				0x04
> > > > 			})
> > > > 			Device (EPUP)
> > > > 			{
> > > > 				Name (_ADR, Zero)
> > > > 				Method (_RMV, 0, NotSerialized)
> > > > 				{
> > > > 					Return (One)
> > > > 				}
> > > > 			}
> > > > 		}
> > > > 	}
> > > > 	...
> > > > 
> > > > Fix this by adding a DMI quirk for the Acer Aspire S5 machine that gives an
> > > > alternative path to the _RMV method.
> > > > 
> > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > ---
> > > >  drivers/pci/hotplug/acpi_pcihp.c | 57 ++++++++++++++++++++++++++++++++++++----
> > > >  1 file changed, 52 insertions(+), 5 deletions(-)
> > > > 
> > > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > > index 2a47e82..99fccf3 100644
> > > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > > @@ -33,6 +33,7 @@
> > > >  #include <linux/acpi.h>
> > > >  #include <linux/pci-acpi.h>
> > > >  #include <linux/slab.h>
> > > > +#include <linux/dmi.h>
> > > >  
> > > >  #define MY_NAME	"acpi_pcihp"
> > > >  
> > > > @@ -408,21 +409,67 @@ got_one:
> > > >  }
> > > >  EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
> > > >  
> > > > +/**
> > > > + * pcihp_is_removable - is the given ACPI device removable
> > > > + * @handle: ACPI handle of the device
> > > > + *
> > > > + * Try to find out whether the given ACPI device is removable by evaluating
> > > > + * its _RMV and returning the result. If we can't find the _RMV directly
> > > > + * under the device use system specific quirks to locate it.
> > > > + */
> > > > +static bool pcihp_is_removable(acpi_handle handle)
> > > > +{
> > > 
> > > People are generally used to seeing DMI lists outside of functions.
> > 
> > OK.
> > 
> > > > +	static const struct dmi_system_id rmv_paths[] = {
> > > > +		{
> > > > +			/*
> > > > +			 * On Acer Aspire S5 the _RMV method for the
> > > > +			 * Thunderbolt host router upstream port is not
> > > > +			 * located directly under the device but it is
> > > > +			 * instead placed a bit deeper in the hierarchy.
> > > > +			 */
> > > > +			.ident = "Acer Aspire S5",
> > > > +			.matches = {
> > > > +				DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> > > > +				DMI_MATCH(DMI_PRODUCT_NAME, "Aspire S5-391"),
> > > > +			},
> > > > +			.driver_data = "HRDN.EPUP._RMV",
> > > 
> > > Use .callback instead? ->
> > > 
> > > > +		},
> > > > +		{ }
> > > > +	};
> > > > +	const struct dmi_system_id *id;
> > > > +	unsigned long long removable;
> > > > +	acpi_status status;
> > > > +
> > > > +	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > > > +	if (ACPI_SUCCESS(status))
> > > > +		return !!removable;
> > > > +
> > > > +	/* Try system specific quirks */
> > > > +	id = dmi_first_match(rmv_paths);
> > > > +	if (id && id->driver_data) {
> > > 
> > > -> And here do
> > > 
> > > 	if (id && id->callback)
> > > 		return id->callback(id);
> > 
> > There is a problem with the above that we can't pass an ACPI handle to the
> > callback function.
> 
> Ah, right.
> 
> Well, you can do
> 
> 	if (id && id->driver_data) {
> 		bool (*callback)(acpi_handle) = id->driver_data;
> 
> 		return callback(handle);
> 	}
> 
> although it's a bit hackish.

I'm thinking that passing just the path from driver_data might be simpler
in this case ;-) But I'm fine with changing it to be a callback as well.

> > > 
> > > > +		char path[64];
> > > > +
> > > > +		strlcpy(path, id->driver_data, sizeof(path));
> 
> BTW, why didn't you want to pass id->driver_data directly here?

acpi_evaluate_integer() takes acpi_string as parameter which is 'char *',
not 'const char *'.

Doing:

	.driver_data = "HRDN.EPUP._RMV",

might place that string to a read-only area (as it is constant), if I
understand C correctly. So even though I know that acpi_evaluate_interger()
doesn't change the parameter, there's no guarantee that it doesn't do that
in the future.

> 
> > > > +		status = acpi_evaluate_integer(handle, path, NULL, &removable);
> > > > +		if (ACPI_SUCCESS(status))
> > > > +			return !!removable;
> > > > +	}
> > > > +
> > > > +	return false;
> > > > +}
> > > > +
> 
> Thanks,
> Rafael
> 
> 
> -- 
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.
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Rafael J. Wysocki - July 4, 2013, 1:53 p.m.
On Thursday, July 04, 2013 04:33:14 PM Mika Westerberg wrote:
> On Thu, Jul 04, 2013 at 03:14:58PM +0200, Rafael J. Wysocki wrote:
> > On Thursday, July 04, 2013 03:53:38 PM Mika Westerberg wrote:
> > > On Thu, Jul 04, 2013 at 02:36:00PM +0200, Rafael J. Wysocki wrote:
> > > > On Thursday, July 04, 2013 11:58:44 AM Mika Westerberg wrote:
> > > > > On Wed, Jul 03, 2013 at 11:40:42PM +0200, Rafael J. Wysocki wrote:
> > > > > > On Wednesday, July 03, 2013 05:04:53 PM Mika Westerberg wrote:
> > > > > > > From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> > > > > > > 
> > > > > > > Correct ACPI PCI hotplug imeplementation should have _RMV method in a
> > > > > > > PCI slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > > > > deeper in hierarchy:
> > > > > > > 
> > > > > > > Device (RP05)
> > > > > > > {
> > > > > > >    // ...
> > > > > > >    Device (HRUP)
> > > > > > >    {
> > > > > > >        // ...
> > > > > > >        Device (HRDN)
> > > > > > >        {
> > > > > > >            // ...
> > > > > > >            Device (EPUP)
> > > > > > >            {
> > > > > > >                // ...
> > > > > > >                Method (_RMV, 0, NotSerialized)  // _RMV: Removal Status
> > > > > > >                {
> > > > > > >                    Return (One)
> > > > > > >                }
> > > > > > >            }
> > > > > > >        }
> > > > > > >    }
> > > > > > > }
> > > > > > > 
> > > > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > > > ---
> > > > > > >  drivers/pci/hotplug/acpi_pcihp.c | 13 +++++++++++++
> > > > > > >  1 file changed, 13 insertions(+)
> > > > > > > 
> > > > > > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > > > index 2a47e82..d92ebfb 100644
> > > > > > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > > > > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > > > @@ -422,6 +422,19 @@ static int pcihp_is_ejectable(acpi_handle handle)
> > > > > > >  	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > > > > > >  	if (ACPI_SUCCESS(status) && removable)
> > > > > > >  		return 1;
> > > > > > > +
> > > > > > > +	/*
> > > > > > > +	 * Workaround for Thunderbolt implementation on Acer Aspire S5.
> > > > > > > +	 *
> > > > > > > +	 * Correct ACPI PCI hotplug imeplementation has _RMV method in a PCI
> > > > > > > +	 * slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > > > > > +	 * deeper in hierarchy.
> > > > > > > +	 */
> > > > > > > +	status = acpi_evaluate_integer(handle, "HRDN.EPUP._RMV", NULL,
> > > > > > > +			&removable);
> > > > > > 
> > > > > > Well, calling stuff like this directly from a general function is kind of ugly.
> > > > > > 
> > > > > > Can we use something like a quirk instead?  A DMI check or something?
> > > > > 
> > > > > Sure we can. How about something like the patch below?
> > > > 
> > > > Well, it goes into the right (to me) direction. :-)
> > > > 
> > > > Some comments below.
> > > > 
> > > > > From: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > Subject: [PATCH] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5
> > > > > 
> > > > > The acpiphp driver finds out whether the device is removable by checking
> > > > > whether it has _RMV method directly behind it (and if it returns 1).
> > > > > However, at least on Acer Aspire S5 with Thunderbolt host router has this
> > > > > method placed behind a device called EPUP (endpoint upstream port?) and not
> > > > > in the usual place expected by the acpiphp driver. The ASL code below shows
> > > > > how this is done on that machine:
> > > > > 
> > > > > Device (RP05)
> > > > > {
> > > > > 	...
> > > > > 	Device (HRUP)
> > > > > 	{
> > > > > 		Name (_ADR, Zero)
> > > > > 		Name (_PRW, Package (0x02)
> > > > > 		{
> > > > > 			0x09,
> > > > > 			0x04
> > > > > 		})
> > > > > 		Device (HRDN)
> > > > > 		{
> > > > > 			Name (_ADR, 0x00040000)
> > > > > 			Name (_PRW, Package (0x02)
> > > > > 			{
> > > > > 				0x09,
> > > > > 				0x04
> > > > > 			})
> > > > > 			Device (EPUP)
> > > > > 			{
> > > > > 				Name (_ADR, Zero)
> > > > > 				Method (_RMV, 0, NotSerialized)
> > > > > 				{
> > > > > 					Return (One)
> > > > > 				}
> > > > > 			}
> > > > > 		}
> > > > > 	}
> > > > > 	...
> > > > > 
> > > > > Fix this by adding a DMI quirk for the Acer Aspire S5 machine that gives an
> > > > > alternative path to the _RMV method.
> > > > > 
> > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > ---
> > > > >  drivers/pci/hotplug/acpi_pcihp.c | 57 ++++++++++++++++++++++++++++++++++++----
> > > > >  1 file changed, 52 insertions(+), 5 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > index 2a47e82..99fccf3 100644
> > > > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > > > @@ -33,6 +33,7 @@
> > > > >  #include <linux/acpi.h>
> > > > >  #include <linux/pci-acpi.h>
> > > > >  #include <linux/slab.h>
> > > > > +#include <linux/dmi.h>
> > > > >  
> > > > >  #define MY_NAME	"acpi_pcihp"
> > > > >  
> > > > > @@ -408,21 +409,67 @@ got_one:
> > > > >  }
> > > > >  EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
> > > > >  
> > > > > +/**
> > > > > + * pcihp_is_removable - is the given ACPI device removable
> > > > > + * @handle: ACPI handle of the device
> > > > > + *
> > > > > + * Try to find out whether the given ACPI device is removable by evaluating
> > > > > + * its _RMV and returning the result. If we can't find the _RMV directly
> > > > > + * under the device use system specific quirks to locate it.
> > > > > + */
> > > > > +static bool pcihp_is_removable(acpi_handle handle)
> > > > > +{
> > > > 
> > > > People are generally used to seeing DMI lists outside of functions.
> > > 
> > > OK.
> > > 
> > > > > +	static const struct dmi_system_id rmv_paths[] = {
> > > > > +		{
> > > > > +			/*
> > > > > +			 * On Acer Aspire S5 the _RMV method for the
> > > > > +			 * Thunderbolt host router upstream port is not
> > > > > +			 * located directly under the device but it is
> > > > > +			 * instead placed a bit deeper in the hierarchy.
> > > > > +			 */
> > > > > +			.ident = "Acer Aspire S5",
> > > > > +			.matches = {
> > > > > +				DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> > > > > +				DMI_MATCH(DMI_PRODUCT_NAME, "Aspire S5-391"),
> > > > > +			},
> > > > > +			.driver_data = "HRDN.EPUP._RMV",
> > > > 
> > > > Use .callback instead? ->
> > > > 
> > > > > +		},
> > > > > +		{ }
> > > > > +	};
> > > > > +	const struct dmi_system_id *id;
> > > > > +	unsigned long long removable;
> > > > > +	acpi_status status;
> > > > > +
> > > > > +	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > > > > +	if (ACPI_SUCCESS(status))
> > > > > +		return !!removable;
> > > > > +
> > > > > +	/* Try system specific quirks */
> > > > > +	id = dmi_first_match(rmv_paths);
> > > > > +	if (id && id->driver_data) {
> > > > 
> > > > -> And here do
> > > > 
> > > > 	if (id && id->callback)
> > > > 		return id->callback(id);
> > > 
> > > There is a problem with the above that we can't pass an ACPI handle to the
> > > callback function.
> > 
> > Ah, right.
> > 
> > Well, you can do
> > 
> > 	if (id && id->driver_data) {
> > 		bool (*callback)(acpi_handle) = id->driver_data;
> > 
> > 		return callback(handle);
> > 	}
> > 
> > although it's a bit hackish.
> 
> I'm thinking that passing just the path from driver_data might be simpler
> in this case ;-) But I'm fine with changing it to be a callback as well.

No, it probably isn't worth the effort for just one system.

> > > > 
> > > > > +		char path[64];
> > > > > +
> > > > > +		strlcpy(path, id->driver_data, sizeof(path));
> > 
> > BTW, why didn't you want to pass id->driver_data directly here?
> 
> acpi_evaluate_integer() takes acpi_string as parameter which is 'char *',
> not 'const char *'.
> 
> Doing:
> 
> 	.driver_data = "HRDN.EPUP._RMV",
> 
> might place that string to a read-only area (as it is constant), if I
> understand C correctly. So even though I know that acpi_evaluate_interger()
> doesn't change the parameter, there's no guarantee that it doesn't do that
> in the future.

I think you can safely assume that acpi_evaluate_integer() won't try to modify
path (there are too many places where string literals are passed to it).

IOW, please just pass id->driver_data to it.

> 
> > 
> > > > > +		status = acpi_evaluate_integer(handle, path, NULL, &removable);
> > > > > +		if (ACPI_SUCCESS(status))
> > > > > +			return !!removable;
> > > > > +	}
> > > > > +
> > > > > +	return false;
> > > > > +}
> > > > > +

Thanks,
Rafael

Patch

diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
index 2a47e82..99fccf3 100644
--- a/drivers/pci/hotplug/acpi_pcihp.c
+++ b/drivers/pci/hotplug/acpi_pcihp.c
@@ -33,6 +33,7 @@ 
 #include <linux/acpi.h>
 #include <linux/pci-acpi.h>
 #include <linux/slab.h>
+#include <linux/dmi.h>
 
 #define MY_NAME	"acpi_pcihp"
 
@@ -408,21 +409,67 @@  got_one:
 }
 EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
 
+/**
+ * pcihp_is_removable - is the given ACPI device removable
+ * @handle: ACPI handle of the device
+ *
+ * Try to find out whether the given ACPI device is removable by evaluating
+ * its _RMV and returning the result. If we can't find the _RMV directly
+ * under the device use system specific quirks to locate it.
+ */
+static bool pcihp_is_removable(acpi_handle handle)
+{
+	static const struct dmi_system_id rmv_paths[] = {
+		{
+			/*
+			 * On Acer Aspire S5 the _RMV method for the
+			 * Thunderbolt host router upstream port is not
+			 * located directly under the device but it is
+			 * instead placed a bit deeper in the hierarchy.
+			 */
+			.ident = "Acer Aspire S5",
+			.matches = {
+				DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
+				DMI_MATCH(DMI_PRODUCT_NAME, "Aspire S5-391"),
+			},
+			.driver_data = "HRDN.EPUP._RMV",
+		},
+		{ }
+	};
+	const struct dmi_system_id *id;
+	unsigned long long removable;
+	acpi_status status;
+
+	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
+	if (ACPI_SUCCESS(status))
+		return !!removable;
+
+	/* Try system specific quirks */
+	id = dmi_first_match(rmv_paths);
+	if (id && id->driver_data) {
+		char path[64];
+
+		strlcpy(path, id->driver_data, sizeof(path));
+		status = acpi_evaluate_integer(handle, path, NULL, &removable);
+		if (ACPI_SUCCESS(status))
+			return !!removable;
+	}
+
+	return false;
+}
+
 static int pcihp_is_ejectable(acpi_handle handle)
 {
 	acpi_status status;
 	acpi_handle tmp;
-	unsigned long long removable;
+
 	status = acpi_get_handle(handle, "_ADR", &tmp);
 	if (ACPI_FAILURE(status))
 		return 0;
 	status = acpi_get_handle(handle, "_EJ0", &tmp);
 	if (ACPI_SUCCESS(status))
 		return 1;
-	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
-	if (ACPI_SUCCESS(status) && removable)
-		return 1;
-	return 0;
+	return pcihp_is_removable(handle);
 }
 
 /**