Hi
On Sat, Nov 30, 2013 at 2:52 PM, Bruno Prémont
<bonbons@xxxxxxxxxxxxxxxxx> wrote:
> With commit b4aa0163056b6c70029b6e8619ce07c274351f42 Matthew Garret
> 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".
>
> 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 x86's pci_fixup_video().
>
> Notes:
> - Other architectures with PCI GPU might need a similar fixup.
> - If CONFIG_VGA_ARB is unset vga_default_device() is only available
> as a stub that returns NULL, making this adjustment insufficient.
> Unsetting CONFIG_VGA_ARB requires CONFIG_EXPERT=y though.
>
> Signed-off-by: Bruno Prémont <bonbons@xxxxxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/vga.h | 6 ------
> arch/x86/pci/fixup.c | 21 +++++++++++++++++++++
> drivers/video/efifb.c | 38 --------------------------------------
> 3 files changed, 21 insertions(+), 44 deletions(-)
>
> 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 f5809fa..440343e 100644
> --- a/arch/x86/pci/fixup.c
> +++ b/arch/x86/pci/fixup.c
> @@ -6,6 +6,7 @@
> #include <linux/dmi.h>
> #include <linux/pci.h>
> #include <linux/init.h>
> +#include <linux/screen_info.h>
> #include <linux/vgaarb.h>
> #include <asm/pci_x86.h>
>
> @@ -323,6 +324,26 @@ 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;
> +
> + 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)
pci_resource_end() returns the address of the end, not the length, so
we have a double off-by-one error here, don't we?
Shouldn't this be:
(screen_info.lfb_base +
screen_info.lfb_size) <= end + 1)
Oh, and lfb_size is in multiples of 0xffff, so it actually needs to be:
(screen_info.lfb_base +
((u64)screen_info.lfb_size << 16)) <= end + 1)
I know, it's copy/paste, but we could still fix it here.
> + vga_set_default_device(pdev);
> + }
> + }
> +
> /* Is VGA routed to us? */
> bus = pdev->bus;
> while (bus) {
> diff --git a/drivers/video/efifb.c b/drivers/video/efifb.c
> index 7f9ff75..fb3fb50 100644
> --- a/drivers/video/efifb.c
> +++ b/drivers/video/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,
> @@ -85,18 +83,6 @@ 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;
> @@ -127,30 +113,6 @@ static int efifb_setup(char *options)
> }
> }
I wonder whether we should move the efifb_setup() argument parsing to
x86/kernel/sysfb.c now. Because currently we break simplefb-conversion
and the vga_boot flag if we keep it here.
Otherwise, the patch looks good to me.
Thanks
David
>
> - 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;
> }
>
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