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

On Wednesday, June 13, 2018 05:45:48 PM Ard Biesheuvel wrote:

On 18 May 2018 at 16:17, Sinan Kaya [off-list ref] wrote:

quoted

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, linelength200, pages=1
efifb: scrolling: redraw
efifb: Truecolor: size=8:8:8:8, shift$:16:8:0

Use the host bridge offset information to convert bus address to
resource address in the fixup.

Signed-off-by: Sinan Kaya <redacted>

Reviewed-by: Ard Biesheuvel <redacted>

Bartlomiej, could you please take these via the fbdev tree for v4.19?

Sure, I will queue it after the current merge window.

Peter already gave his ack but Sinan dropped it (presumably because of
the split in v2)

Peter, can I (re)add your ACK to V2 patches?

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics