Re: [PATCH V2 2/2] efi/fb: Convert PCI bus address to resource if translated by the bridge

[okaya]

On 2018-06-13 11:45, Ard Biesheuvel wrote:
> On 18 May 2018 at 16:17, Sinan Kaya <okaya@xxxxxxxxxxxxxx> wrote:
> > A host bridge is allowed to remap BAR addresses using _TRA attribute 
> > in
> > _CRS windows.
> >
> > pci_bus 0000:00: root bus resource [mem 0x80100100000-0x8011fffffff 
> > window] (bus address [0x00100000-0x1fffffff])
> > pci 0000:02:00.0: reg 0x10: [mem 0x8011e000000-0x8011effffff]
> >
> > When a VGA device is behind such a host bridge and the resource is
> > translated efifb driver is trying to do ioremap against bus address
> > rather than the resource address and is failing to probe.
> >
> > efifb: probing for efifb
> > efifb: cannot reserve video memory at 0x1e000000
> > efifb: framebuffer at 0x1e000000, using 1920k, total 1875k
> > efifb: mode is 800x600x32, linelength=3200, pages=1
> > efifb: scrolling: redraw
> > efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
> >
> > Use the host bridge offset information to convert bus address to
> > resource address in the fixup.
> >
> > Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>
> Bartlomiej, could you please take these via the fbdev tree for v4.19?
> Peter already gave his ack but Sinan dropped it (presumably because of
> the split in v2)
>
> Sinan, does this need to go to -stable? I.e., has it ever worked 
> before?

Yes, it needs to go to stable. It never worked before. Issue was found 
during a graphics bring up with AST driver.

It needs a 32 bit graphics card and a 32 bit translating host bridge to 
hit the issue.

> > ---
> >  drivers/video/fbdev/efifb.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> > index 6daac8d..429cc85 100644
> > --- a/drivers/video/fbdev/efifb.c
> > +++ b/drivers/video/fbdev/efifb.c
> > @@ -431,6 +431,7 @@ static void efifb_fixup_resources(struct pci_dev 
> > *dev)
> >                 .end = screen_info.lfb_base + screen_info.lfb_size - 
> > 1,
> >                 .flags = IORESOURCE_MEM,
> >         };
> > +       struct pci_bus_region region;
> >         int i;
> >
> >         if (efifb_pci_dev || screen_info.orig_video_isVGA != 
> > VIDEO_TYPE_EFI)
> > @@ -442,6 +443,10 @@ static void efifb_fixup_resources(struct pci_dev 
> > *dev)
> >         if (!screen_res.start)
> >                 return;
> >
> > +       region.start = screen_res.start;
> > +       region.end = screen_res.end;
> > +       pcibios_bus_to_resource(dev->bus, &screen_res, &region);
> > +
> >         for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
> >                 struct resource *res = &dev->resource[i];
> >
> > --
> > 2.7.4
> >
> >
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