| Message ID | 1448896304-87928-15-git-send-email-andriy.shevchenko@linux.intel.com |
|---|---|
| State | Not Applicable |
| Headers | show |
On Mon, Nov 30, 2015 at 05:11:42PM +0200, Andy Shevchenko wrote: > From: Mika Westerberg <mika.westerberg@linux.intel.com> > > Intel Skylake the LPSS I2C pad circuit has internal delays that require > programming non-zero SDA hold time for the I2C host controller. If this is > not done communication to slave devices may fail with arbitration lost > errors like the one seen below taken from Lenovo Yoga 900: > > i2c_hid i2c-SYNA2B29:00: Fetching the HID descriptor > i2c_hid i2c-SYNA2B29:00: __i2c_hid_command: cmd=20 00 > i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration > > To fix this we follow what the Windows driver is doing and pass the default > SDA hold time of 230 ns to all Intel Skylake host controllers. This still > allows the platform to override these values by passing special ACPI > methods SSCN and FMCN. > > Reported-by: Kevin Fenzi <kevin@scrye.com> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> There has been a request to get this into stable: https://bugzilla.kernel.org/show_bug.cgi?id=108581 Since we probably don't want to backport the whole device_property series, is there a simpler fix to backport for stable?
On Mon, Feb 08, 2016 at 11:09:43AM +0100, Wolfram Sang wrote: > On Mon, Nov 30, 2015 at 05:11:42PM +0200, Andy Shevchenko wrote: > > From: Mika Westerberg <mika.westerberg@linux.intel.com> > > > > Intel Skylake the LPSS I2C pad circuit has internal delays that require > > programming non-zero SDA hold time for the I2C host controller. If this is > > not done communication to slave devices may fail with arbitration lost > > errors like the one seen below taken from Lenovo Yoga 900: > > > > i2c_hid i2c-SYNA2B29:00: Fetching the HID descriptor > > i2c_hid i2c-SYNA2B29:00: __i2c_hid_command: cmd=20 00 > > i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration > > > > To fix this we follow what the Windows driver is doing and pass the default > > SDA hold time of 230 ns to all Intel Skylake host controllers. This still > > allows the platform to override these values by passing special ACPI > > methods SSCN and FMCN. > > > > Reported-by: Kevin Fenzi <kevin@scrye.com> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > There has been a request to get this into stable: > > https://bugzilla.kernel.org/show_bug.cgi?id=108581 > > Since we probably don't want to backport the whole device_property > series, is there a simpler fix to backport for stable? Basically all it needs is to have: dev->sda_hold_time = 28 in dw_i2c_acpi_configure(). However, we cannot just unconditionally set it as it will break existing non-SKL systems so there should be some way to check if this is SKL or not. Perhaps we could look for DMI entries of the affected machines? BTW, this is not a regression in a sense as SKL I2C never worked before this series. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Feb 8, 2016 at 12:29 PM, Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > On Mon, Feb 08, 2016 at 11:09:43AM +0100, Wolfram Sang wrote: >> On Mon, Nov 30, 2015 at 05:11:42PM +0200, Andy Shevchenko wrote: >> There has been a request to get this into stable: >> >> https://bugzilla.kernel.org/show_bug.cgi?id=108581 >> >> Since we probably don't want to backport the whole device_property >> series, is there a simpler fix to backport for stable? > > Basically all it needs is to have: > > dev->sda_hold_time = 28 > > in dw_i2c_acpi_configure(). However, we cannot just unconditionally set > it as it will break existing non-SKL systems so there should be some way > to check if this is SKL or not. Perhaps we could look for DMI entries of > the affected machines? > > BTW, this is not a regression in a sense as SKL I2C never worked before > this series. I could add that "backporting" something which is drastically different to the original mainstream may probably prevent a smooth backporting the fixes come later if any. Thus, I would try to port as much closer as we can to the existing upstream code.
On Mon, 30 Nov 2015, Andy Shevchenko wrote: > From: Mika Westerberg <mika.westerberg@linux.intel.com> > > Intel Skylake the LPSS I2C pad circuit has internal delays that require > programming non-zero SDA hold time for the I2C host controller. If this is > not done communication to slave devices may fail with arbitration lost > errors like the one seen below taken from Lenovo Yoga 900: > > i2c_hid i2c-SYNA2B29:00: Fetching the HID descriptor > i2c_hid i2c-SYNA2B29:00: __i2c_hid_command: cmd=20 00 > i2c_designware i2c_designware.1: i2c_dw_handle_tx_abort: lost arbitration > > To fix this we follow what the Windows driver is doing and pass the default > SDA hold time of 230 ns to all Intel Skylake host controllers. This still > allows the platform to override these values by passing special ACPI > methods SSCN and FMCN. > > Reported-by: Kevin Fenzi <kevin@scrye.com> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > drivers/mfd/intel-lpss-acpi.c | 19 +++++++++++++++++-- > drivers/mfd/intel-lpss-pci.c | 31 +++++++++++++++++++++++-------- > 2 files changed, 40 insertions(+), 10 deletions(-) Seems fine in principle. Acked-by: Lee Jones <lee.jones@linaro.org> > diff --git a/drivers/mfd/intel-lpss-acpi.c b/drivers/mfd/intel-lpss-acpi.c > index b6fd904..06f00d6 100644 > --- a/drivers/mfd/intel-lpss-acpi.c > +++ b/drivers/mfd/intel-lpss-acpi.c > @@ -18,6 +18,7 @@ > #include <linux/pm.h> > #include <linux/pm_runtime.h> > #include <linux/platform_device.h> > +#include <linux/property.h> > > #include "intel-lpss.h" > > @@ -25,6 +26,20 @@ static const struct intel_lpss_platform_info spt_info = { > .clk_rate = 120000000, > }; > > +static struct property_entry spt_i2c_properties[] = { > + PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230), > + { }, > +}; > + > +static struct property_set spt_i2c_pset = { > + .properties = spt_i2c_properties, > +}; > + > +static const struct intel_lpss_platform_info spt_i2c_info = { > + .clk_rate = 120000000, > + .pset = &spt_i2c_pset, > +}; > + > static const struct intel_lpss_platform_info bxt_info = { > .clk_rate = 100000000, > }; > @@ -35,8 +50,8 @@ static const struct intel_lpss_platform_info bxt_i2c_info = { > > static const struct acpi_device_id intel_lpss_acpi_ids[] = { > /* SPT */ > - { "INT3446", (kernel_ulong_t)&spt_info }, > - { "INT3447", (kernel_ulong_t)&spt_info }, > + { "INT3446", (kernel_ulong_t)&spt_i2c_info }, > + { "INT3447", (kernel_ulong_t)&spt_i2c_info }, > /* BXT */ > { "80860AAC", (kernel_ulong_t)&bxt_i2c_info }, > { "80860ABC", (kernel_ulong_t)&bxt_info }, > diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c > index 5bfdfcc..a677480 100644 > --- a/drivers/mfd/intel-lpss-pci.c > +++ b/drivers/mfd/intel-lpss-pci.c > @@ -17,6 +17,7 @@ > #include <linux/pci.h> > #include <linux/pm.h> > #include <linux/pm_runtime.h> > +#include <linux/property.h> > > #include "intel-lpss.h" > > @@ -65,6 +66,20 @@ static const struct intel_lpss_platform_info spt_info = { > .clk_rate = 120000000, > }; > > +static struct property_entry spt_i2c_properties[] = { > + PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230), > + { }, > +}; > + > +static struct property_set spt_i2c_pset = { > + .properties = spt_i2c_properties, > +}; > + > +static const struct intel_lpss_platform_info spt_i2c_info = { > + .clk_rate = 120000000, > + .pset = &spt_i2c_pset, > +}; > + > static const struct intel_lpss_platform_info spt_uart_info = { > .clk_rate = 120000000, > .clk_con_id = "baudclk", > @@ -121,20 +136,20 @@ static const struct pci_device_id intel_lpss_pci_ids[] = { > { PCI_VDEVICE(INTEL, 0x9d28), (kernel_ulong_t)&spt_uart_info }, > { PCI_VDEVICE(INTEL, 0x9d29), (kernel_ulong_t)&spt_info }, > { PCI_VDEVICE(INTEL, 0x9d2a), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_info }, > + { PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_i2c_info }, > + { PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_i2c_info }, > + { PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_i2c_info }, > + { PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_i2c_info }, > + { PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_i2c_info }, > + { PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_i2c_info }, > { PCI_VDEVICE(INTEL, 0x9d66), (kernel_ulong_t)&spt_uart_info }, > /* SPT-H */ > { PCI_VDEVICE(INTEL, 0xa127), (kernel_ulong_t)&spt_uart_info }, > { PCI_VDEVICE(INTEL, 0xa128), (kernel_ulong_t)&spt_uart_info }, > { PCI_VDEVICE(INTEL, 0xa129), (kernel_ulong_t)&spt_info }, > { PCI_VDEVICE(INTEL, 0xa12a), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_info }, > - { PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_info }, > + { PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_i2c_info }, > + { PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_i2c_info }, > { PCI_VDEVICE(INTEL, 0xa166), (kernel_ulong_t)&spt_uart_info }, > { } > };
diff --git a/drivers/mfd/intel-lpss-acpi.c b/drivers/mfd/intel-lpss-acpi.c index b6fd904..06f00d6 100644 --- a/drivers/mfd/intel-lpss-acpi.c +++ b/drivers/mfd/intel-lpss-acpi.c @@ -18,6 +18,7 @@ #include <linux/pm.h> #include <linux/pm_runtime.h> #include <linux/platform_device.h> +#include <linux/property.h> #include "intel-lpss.h" @@ -25,6 +26,20 @@ static const struct intel_lpss_platform_info spt_info = { .clk_rate = 120000000, }; +static struct property_entry spt_i2c_properties[] = { + PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230), + { }, +}; + +static struct property_set spt_i2c_pset = { + .properties = spt_i2c_properties, +}; + +static const struct intel_lpss_platform_info spt_i2c_info = { + .clk_rate = 120000000, + .pset = &spt_i2c_pset, +}; + static const struct intel_lpss_platform_info bxt_info = { .clk_rate = 100000000, }; @@ -35,8 +50,8 @@ static const struct intel_lpss_platform_info bxt_i2c_info = { static const struct acpi_device_id intel_lpss_acpi_ids[] = { /* SPT */ - { "INT3446", (kernel_ulong_t)&spt_info }, - { "INT3447", (kernel_ulong_t)&spt_info }, + { "INT3446", (kernel_ulong_t)&spt_i2c_info }, + { "INT3447", (kernel_ulong_t)&spt_i2c_info }, /* BXT */ { "80860AAC", (kernel_ulong_t)&bxt_i2c_info }, { "80860ABC", (kernel_ulong_t)&bxt_info }, diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c index 5bfdfcc..a677480 100644 --- a/drivers/mfd/intel-lpss-pci.c +++ b/drivers/mfd/intel-lpss-pci.c @@ -17,6 +17,7 @@ #include <linux/pci.h> #include <linux/pm.h> #include <linux/pm_runtime.h> +#include <linux/property.h> #include "intel-lpss.h" @@ -65,6 +66,20 @@ static const struct intel_lpss_platform_info spt_info = { .clk_rate = 120000000, }; +static struct property_entry spt_i2c_properties[] = { + PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230), + { }, +}; + +static struct property_set spt_i2c_pset = { + .properties = spt_i2c_properties, +}; + +static const struct intel_lpss_platform_info spt_i2c_info = { + .clk_rate = 120000000, + .pset = &spt_i2c_pset, +}; + static const struct intel_lpss_platform_info spt_uart_info = { .clk_rate = 120000000, .clk_con_id = "baudclk", @@ -121,20 +136,20 @@ static const struct pci_device_id intel_lpss_pci_ids[] = { { PCI_VDEVICE(INTEL, 0x9d28), (kernel_ulong_t)&spt_uart_info }, { PCI_VDEVICE(INTEL, 0x9d29), (kernel_ulong_t)&spt_info }, { PCI_VDEVICE(INTEL, 0x9d2a), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_info }, + { PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_i2c_info }, + { PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_i2c_info }, + { PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_i2c_info }, + { PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_i2c_info }, + { PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_i2c_info }, + { PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_i2c_info }, { PCI_VDEVICE(INTEL, 0x9d66), (kernel_ulong_t)&spt_uart_info }, /* SPT-H */ { PCI_VDEVICE(INTEL, 0xa127), (kernel_ulong_t)&spt_uart_info }, { PCI_VDEVICE(INTEL, 0xa128), (kernel_ulong_t)&spt_uart_info }, { PCI_VDEVICE(INTEL, 0xa129), (kernel_ulong_t)&spt_info }, { PCI_VDEVICE(INTEL, 0xa12a), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_info }, - { PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_info }, + { PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_i2c_info }, + { PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_i2c_info }, { PCI_VDEVICE(INTEL, 0xa166), (kernel_ulong_t)&spt_uart_info }, { } };