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SubjectRe: [PATCH V2 2/2] efi/fb: Convert PCI bus address to resource if translated by the bridge
Minor subject nit: From the caller's point of view, we must convert a bus
address to a resource *always* (the caller has no knowledge of "whether it
is translated by the host bridge").

On Fri, May 18, 2018 at 10:17:51AM -0400, Sinan Kaya wrote:
> A host bridge is allowed to remap BAR addresses using _TRA attribute in
> _CRS windows.

Also, _TRA/_CRS are ACPI-specific terms and non-ACPI host bridges can
also do the same sort of translation. Another trivial nit.

> 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@codeaurora.org>

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>

Thanks a lot for fixing this!

> ---
> 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
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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