Re: [PATCH 1/2] x86, ia64: Move EFI_FB vga_default_device() initialization to pci_vga_fixup()

["Bruno Prémont" <bonbons@linux-vserver.org>]

On Tue, 17 Jun 2014 16:35:42 -0600 Bjorn Helgaas wrote:
> On Mon, Jun 02, 2014 at 08:19:26PM +0200, Bruno Prémont wrote:
> > With commit b4aa0163056b ("efifb: Implement vga_default_device() (v2)")
> > Matthew Garrett introduced a efifb vga_default_device() so that EFI
> > systems that do not load shadow VBIOS or setup VGA get proper value for
> > boot_vga PCI sysfs attribute on the corresponding PCI device.
> > 
> > Xorg is refusing to detect devices when boot_vga=0 which is the case on
> > some EFI system (e.g. MacBookAir2,1). Xorg detects the GPU and finds
> > the dri device but then bails out with "no devices detected".
> > 
> > Note: When vga_default_device() is set boot_vga PCI sysfs attribute
> > reflects its state. When unset this attribute is 1 whenever
> > IORESOURCE_ROM_SHADOW flag is set.
> > 
> > With introduction of sysfb/simplefb/simpledrm efifb is getting obsolete
> > while having native drivers for the GPU also makes selecting
> > sysfb/efifb optional.
> > 
> > Remove the efifb implementation of vga_default_device() and initialize
> > vgaarb's vga_default_device() with the PCI GPU that matches boot
> > screen_info in pci_fixup_video().
> > 
> > Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
> > ---
> >  arch/ia64/pci/fixup.c       | 21 +++++++++++++++++++++
> >  arch/x86/include/asm/vga.h  |  6 ------
> >  arch/x86/pci/fixup.c        | 21 +++++++++++++++++++++
> >  drivers/video/fbdev/efifb.c | 38 --------------------------------------
> >  4 files changed, 42 insertions(+), 44 deletions(-)
> 
> Something went wrong here.  It seems like the [2/2] patch should have
> been [1/2], and this one should be [2/2].  And this one modifies both
> arch/ia64/pci/fixup.c and arch/x86/pci/fixup.c, but the other patch
> mostly combines them, so I don't see how this one applies.

I ordered both patches the other way around from your explicit ordering
proposal following the stable kernel suggestion following it.

My patch 1/2 fixes the encountered issue and is the one that may go
stable while my patch 2/2 performs unification of common code.
The unification will need to be placed somewhere else than in vgaarb.c
if one wants to keep current fixup working with CONFIG_VGA_ARB=n.

> And there were unrelated (trivial) changes to these files, so they
> need to be rebased to v3.16-rc1.  I'd take care of the rebase, but
> I don't understand the other stuff I mentioned.

Ok

Bruno

> Bjorn
> 
> > diff --git a/arch/ia64/pci/fixup.c b/arch/ia64/pci/fixup.c
> > index eee069a..9ed5bef 100644
> > --- a/arch/ia64/pci/fixup.c
> > +++ b/arch/ia64/pci/fixup.c
> > @@ -37,6 +37,27 @@ static void pci_fixup_video(struct pci_dev *pdev)
> >  		return;
> >  	/* Maybe, this machine supports legacy memory map. */
> >  
> > +	if (!vga_default_device()) {
> > +		resource_size_t start, end;
> > +		int i;
> > +
> > +		/* Does firmware framebuffer belong to us? */
> > +		for (i=0; i < DEVICE_COUNT_RESOURCE; i++) {
> > +			if (!(pci_resource_flags(pdev, i) & IORESOURCE_MEM))
> > +				continue;
> > +
> > +			start = pci_resource_start(pdev, i);
> > +			end  = pci_resource_end(pdev, i);
> > +
> > +			if (!start || !end)
> > +				continue;
> > +
> > +			if (screen_info.lfb_base >= start &&
> > +				(screen_info.lfb_base + screen_info.lfb_size) < end)
> > +				vga_set_default_device(pdev);
> > +		}
> > +	}
> > +
> >  	/* Is VGA routed to us? */
> >  	bus = pdev->bus;
> >  	while (bus) {
> > diff --git a/arch/x86/include/asm/vga.h b/arch/x86/include/asm/vga.h
> > index 44282fb..c4b9dc2 100644
> > --- a/arch/x86/include/asm/vga.h
> > +++ b/arch/x86/include/asm/vga.h
> > @@ -17,10 +17,4 @@
> >  #define vga_readb(x) (*(x))
> >  #define vga_writeb(x, y) (*(y) = (x))
> >  
> > -#ifdef CONFIG_FB_EFI
> > -#define __ARCH_HAS_VGA_DEFAULT_DEVICE
> > -extern struct pci_dev *vga_default_device(void);
> > -extern void vga_set_default_device(struct pci_dev *pdev);
> > -#endif
> > -
> >  #endif /* _ASM_X86_VGA_H */
> > diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
> > index 94ae9ae..7246cf2 100644
> > --- a/arch/x86/pci/fixup.c
> > +++ b/arch/x86/pci/fixup.c
> > @@ -325,6 +325,27 @@ static void pci_fixup_video(struct pci_dev *pdev)
> >  	struct pci_bus *bus;
> >  	u16 config;
> >  
> > +	if (!vga_default_device()) {
> > +		resource_size_t start, end;
> > +		int i;
> > +
> > +		/* Does firmware framebuffer belong to us? */
> > +		for (i=0; i < DEVICE_COUNT_RESOURCE; i++) {
> > +			if (!(pci_resource_flags(pdev, i) & IORESOURCE_MEM))
> > +				continue;
> > +
> > +			start = pci_resource_start(pdev, i);
> > +			end  = pci_resource_end(pdev, i);
> > +
> > +			if (!start || !end)
> > +				continue;
> > +
> > +			if (screen_info.lfb_base >= start &&
> > +				(screen_info.lfb_base + screen_info.lfb_size) < end)
> > +				vga_set_default_device(pdev);
> > +		}
> > +	}
> > +
> >  	/* Is VGA routed to us? */
> >  	bus = pdev->bus;
> >  	while (bus) {
> > diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> > index ae9618f..a033180 100644
> > --- a/drivers/video/fbdev/efifb.c
> > +++ b/drivers/video/fbdev/efifb.c
> > @@ -19,8 +19,6 @@
> >  
> >  static bool request_mem_succeeded = false;
> >  
> > -static struct pci_dev *default_vga;
> > -
> >  static struct fb_var_screeninfo efifb_defined = {
> >  	.activate		= FB_ACTIVATE_NOW,
> >  	.height			= -1,
> > @@ -84,18 +82,6 @@ static struct fb_ops efifb_ops = {
> >  	.fb_imageblit	= cfb_imageblit,
> >  };
> >  
> > -struct pci_dev *vga_default_device(void)
> > -{
> > -	return default_vga;
> > -}
> > -
> > -EXPORT_SYMBOL_GPL(vga_default_device);
> > -
> > -void vga_set_default_device(struct pci_dev *pdev)
> > -{
> > -	default_vga = pdev;
> > -}
> > -
> >  static int efifb_setup(char *options)
> >  {
> >  	char *this_opt;
> > @@ -126,30 +112,6 @@ static int efifb_setup(char *options)
> >  		}
> >  	}
> >  
> > -	for_each_pci_dev(dev) {
> > -		int i;
> > -
> > -		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
> > -			continue;
> > -
> > -		for (i=0; i < DEVICE_COUNT_RESOURCE; i++) {
> > -			resource_size_t start, end;
> > -
> > -			if (!(pci_resource_flags(dev, i) & IORESOURCE_MEM))
> > -				continue;
> > -
> > -			start = pci_resource_start(dev, i);
> > -			end  = pci_resource_end(dev, i);
> > -
> > -			if (!start || !end)
> > -				continue;
> > -
> > -			if (screen_info.lfb_base >= start &&
> > -			    (screen_info.lfb_base + screen_info.lfb_size) < end)
> > -				default_vga = dev;
> > -		}
> > -	}
> > -
> >  	return 0;
> >  }
> >  
> > -- 
> > 1.8.5.5
> >