diff mbox series

[v5,09/44] drm: handle HAS_IOPORT dependencies

Message ID 20230522105049.1467313-10-schnelle@linux.ibm.com
State New
Headers show
Series treewide: Remove I/O port accessors for HAS_IOPORT=n | expand

Commit Message

Niklas Schnelle May 22, 2023, 10:50 a.m. UTC
In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
not being declared. We thus need to add HAS_IOPORT as dependency for
those drivers using them. In the bochs driver there is optional MMIO
support detected at runtime, warn if this isn't taken when
HAS_IOPORT is not defined.

There is also a direct and hard coded use in cirrus.c which according to
the comment is only necessary during resume.  Let's just skip this as
for example s390 which doesn't have I/O port support also doesen't
support suspend/resume.

Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 drivers/gpu/drm/qxl/Kconfig   |  1 +
 drivers/gpu/drm/tiny/bochs.c  | 17 +++++++++++++++++
 drivers/gpu/drm/tiny/cirrus.c |  2 ++
 3 files changed, 20 insertions(+)

Comments

Thomas Zimmermann May 22, 2023, 12:38 p.m. UTC | #1
Hi

Am 22.05.23 um 12:50 schrieb Niklas Schnelle:
> In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> not being declared. We thus need to add HAS_IOPORT as dependency for
> those drivers using them. In the bochs driver there is optional MMIO
> support detected at runtime, warn if this isn't taken when
> HAS_IOPORT is not defined.
> 
> There is also a direct and hard coded use in cirrus.c which according to
> the comment is only necessary during resume.  Let's just skip this as
> for example s390 which doesn't have I/O port support also doesen't
> support suspend/resume.

I think we should consider making cirrus depend on HAS_IOPORT. The 
driver is only for qemu's cirrus emulation, which IIRC can only be 
enabled for i586. And it has all been deprecated long ago.

> 
> Co-developed-by: Arnd Bergmann <arnd@kernel.org>
> Signed-off-by: Arnd Bergmann <arnd@kernel.org>
> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
> ---
>   drivers/gpu/drm/qxl/Kconfig   |  1 +
>   drivers/gpu/drm/tiny/bochs.c  | 17 +++++++++++++++++
>   drivers/gpu/drm/tiny/cirrus.c |  2 ++
>   3 files changed, 20 insertions(+)
> 
> diff --git a/drivers/gpu/drm/qxl/Kconfig b/drivers/gpu/drm/qxl/Kconfig
> index ca3f51c2a8fe..d0e0d440c8d9 100644
> --- a/drivers/gpu/drm/qxl/Kconfig
> +++ b/drivers/gpu/drm/qxl/Kconfig
> @@ -2,6 +2,7 @@
>   config DRM_QXL
>   	tristate "QXL virtual GPU"
>   	depends on DRM && PCI && MMU
> +	depends on HAS_IOPORT
>   	select DRM_KMS_HELPER
>   	select DRM_TTM
>   	select DRM_TTM_HELPER
> diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
> index d254679a136e..3710339407cc 100644
> --- a/drivers/gpu/drm/tiny/bochs.c
> +++ b/drivers/gpu/drm/tiny/bochs.c
> @@ -2,6 +2,7 @@
>   
>   #include <linux/module.h>
>   #include <linux/pci.h>
> +#include <asm/bug.h>

Why not <linux/bug.h> ?

>   
>   #include <drm/drm_aperture.h>
>   #include <drm/drm_atomic_helper.h>
> @@ -105,7 +106,9 @@ static void bochs_vga_writeb(struct bochs_device *bochs, u16 ioport, u8 val)
>   
>   		writeb(val, bochs->mmio + offset);
>   	} else {
> +#ifdef CONFIG_HAS_IOPORT
>   		outb(val, ioport);
> +#endif

Would it be feasible to define inb, inw, outb and outw at the top of 
bochs.c if no HAS_IOPORT has been set?  That would avoid the ifdef 
branching within the code.

>   	}
>   }
>   
> @@ -119,7 +122,11 @@ static u8 bochs_vga_readb(struct bochs_device *bochs, u16 ioport)
>   
>   		return readb(bochs->mmio + offset);
>   	} else {
> +#ifdef CONFIG_HAS_IOPORT
>   		return inb(ioport);
> +#else
> +		return 0xff;
> +#endif
>   	}
>   }
>   
> @@ -132,8 +139,12 @@ static u16 bochs_dispi_read(struct bochs_device *bochs, u16 reg)
>   
>   		ret = readw(bochs->mmio + offset);
>   	} else {
> +#ifdef CONFIG_HAS_IOPORT
>   		outw(reg, VBE_DISPI_IOPORT_INDEX);
>   		ret = inw(VBE_DISPI_IOPORT_DATA);
> +#else
> +		ret = 0xffff;
> +#endif
>   	}
>   	return ret;
>   }
> @@ -145,8 +156,10 @@ static void bochs_dispi_write(struct bochs_device *bochs, u16 reg, u16 val)
>   
>   		writew(val, bochs->mmio + offset);
>   	} else {
> +#ifdef CONFIG_HAS_IOPORT
>   		outw(reg, VBE_DISPI_IOPORT_INDEX);
>   		outw(val, VBE_DISPI_IOPORT_DATA);
> +#endif
>   	}
>   }
>   
> @@ -229,6 +242,10 @@ static int bochs_hw_init(struct drm_device *dev)
>   			return -ENOMEM;
>   		}
>   	} else {
> +		if (!IS_ENABLED(CONFIG_HAS_IOPORT)) {
> +			DRM_ERROR("I/O ports are not supported\n");

Use drm_err() here.

Best regards
Thomas

> +			return -EIO;
> +		}
>   		ioaddr = VBE_DISPI_IOPORT_INDEX;
>   		iosize = 2;
>   		if (!request_region(ioaddr, iosize, "bochs-drm")) {
> diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
> index 594bc472862f..c65fea049bc7 100644
> --- a/drivers/gpu/drm/tiny/cirrus.c
> +++ b/drivers/gpu/drm/tiny/cirrus.c
> @@ -508,8 +508,10 @@ static void cirrus_crtc_helper_atomic_enable(struct drm_crtc *crtc,
>   
>   	cirrus_mode_set(cirrus, &crtc_state->mode);
>   
> +#ifdef CONFIG_HAS_IOPORT
>   	/* Unblank (needed on S3 resume, vgabios doesn't do it then) */
>   	outb(VGA_AR_ENABLE_DISPLAY, VGA_ATT_W);
> +#endif
>   
>   	drm_dev_exit(idx);
>   }
Arnd Bergmann May 22, 2023, 1:06 p.m. UTC | #2
On Mon, May 22, 2023, at 14:38, Thomas Zimmermann wrote:
> Am 22.05.23 um 12:50 schrieb Niklas Schnelle:

>> There is also a direct and hard coded use in cirrus.c which according to
>> the comment is only necessary during resume.  Let's just skip this as
>> for example s390 which doesn't have I/O port support also doesen't
>> support suspend/resume.
>
> I think we should consider making cirrus depend on HAS_IOPORT. The 
> driver is only for qemu's cirrus emulation, which IIRC can only be 
> enabled for i586. And it has all been deprecated long ago.

I tried it out in arm64 debvm, and both the kernel and Xorg drivers
are detected just fine according to the log. I only get a black
screen, which could be the result of a missing VGA BIOS or the missing
unblank Port I/O in the driver (I doubt the VGA ports are hooked up
on arm64 qemu), but there is a good chance that it's currently
working for someone else.

      Arnd
Gerd Hoffmann May 22, 2023, 1:14 p.m. UTC | #3
Hi,

> > There is also a direct and hard coded use in cirrus.c which according to
> > the comment is only necessary during resume.  Let's just skip this as
> > for example s390 which doesn't have I/O port support also doesen't
> > support suspend/resume.
> 
> I think we should consider making cirrus depend on HAS_IOPORT. The driver is
> only for qemu's cirrus emulation, which IIRC can only be enabled for i586.

Agree.  cirrus is x86 only (both i386 / x86_64 though).  Just require
HAS_IOPORT and be done with it.

> And it has all been deprecated long ago.

The fact that cirrus used to be the qemu default for many years is
pretty much the only reason it is still somewhat relevant today ...

take care,
  Gerd
diff mbox series

Patch

diff --git a/drivers/gpu/drm/qxl/Kconfig b/drivers/gpu/drm/qxl/Kconfig
index ca3f51c2a8fe..d0e0d440c8d9 100644
--- a/drivers/gpu/drm/qxl/Kconfig
+++ b/drivers/gpu/drm/qxl/Kconfig
@@ -2,6 +2,7 @@ 
 config DRM_QXL
 	tristate "QXL virtual GPU"
 	depends on DRM && PCI && MMU
+	depends on HAS_IOPORT
 	select DRM_KMS_HELPER
 	select DRM_TTM
 	select DRM_TTM_HELPER
diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index d254679a136e..3710339407cc 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -2,6 +2,7 @@ 
 
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <asm/bug.h>
 
 #include <drm/drm_aperture.h>
 #include <drm/drm_atomic_helper.h>
@@ -105,7 +106,9 @@  static void bochs_vga_writeb(struct bochs_device *bochs, u16 ioport, u8 val)
 
 		writeb(val, bochs->mmio + offset);
 	} else {
+#ifdef CONFIG_HAS_IOPORT
 		outb(val, ioport);
+#endif
 	}
 }
 
@@ -119,7 +122,11 @@  static u8 bochs_vga_readb(struct bochs_device *bochs, u16 ioport)
 
 		return readb(bochs->mmio + offset);
 	} else {
+#ifdef CONFIG_HAS_IOPORT
 		return inb(ioport);
+#else
+		return 0xff;
+#endif
 	}
 }
 
@@ -132,8 +139,12 @@  static u16 bochs_dispi_read(struct bochs_device *bochs, u16 reg)
 
 		ret = readw(bochs->mmio + offset);
 	} else {
+#ifdef CONFIG_HAS_IOPORT
 		outw(reg, VBE_DISPI_IOPORT_INDEX);
 		ret = inw(VBE_DISPI_IOPORT_DATA);
+#else
+		ret = 0xffff;
+#endif
 	}
 	return ret;
 }
@@ -145,8 +156,10 @@  static void bochs_dispi_write(struct bochs_device *bochs, u16 reg, u16 val)
 
 		writew(val, bochs->mmio + offset);
 	} else {
+#ifdef CONFIG_HAS_IOPORT
 		outw(reg, VBE_DISPI_IOPORT_INDEX);
 		outw(val, VBE_DISPI_IOPORT_DATA);
+#endif
 	}
 }
 
@@ -229,6 +242,10 @@  static int bochs_hw_init(struct drm_device *dev)
 			return -ENOMEM;
 		}
 	} else {
+		if (!IS_ENABLED(CONFIG_HAS_IOPORT)) {
+			DRM_ERROR("I/O ports are not supported\n");
+			return -EIO;
+		}
 		ioaddr = VBE_DISPI_IOPORT_INDEX;
 		iosize = 2;
 		if (!request_region(ioaddr, iosize, "bochs-drm")) {
diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index 594bc472862f..c65fea049bc7 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c
@@ -508,8 +508,10 @@  static void cirrus_crtc_helper_atomic_enable(struct drm_crtc *crtc,
 
 	cirrus_mode_set(cirrus, &crtc_state->mode);
 
+#ifdef CONFIG_HAS_IOPORT
 	/* Unblank (needed on S3 resume, vgabios doesn't do it then) */
 	outb(VGA_AR_ENABLE_DISPLAY, VGA_ATT_W);
+#endif
 
 	drm_dev_exit(idx);
 }