lkml.org 
[lkml]   [2018]   [Jun]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH V2 2/2] efi/fb: Convert PCI bus address to resource if translated by the bridge
On 2018-06-13 11:45, Ard Biesheuvel wrote:
> On 18 May 2018 at 16:17, Sinan Kaya <okaya@codeaurora.org> 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@codeaurora.org>
>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>
> 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
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

\
 
 \ /
  Last update: 2018-06-13 17:51    [W:0.075 / U:2.188 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site