Re: 2.6.33-rc3: pci host bridge windows ignored (works with pci=use_crs)

[Yinghai Lu]

On Tue, Jan 12, 2010 at 9:37 PM, Jeff Garrett <jeff@xxxxxxxxxxxx> wrote:
> Took a stab at getting the right emails.  If I missed anyone, sorry...
>
> I have a desktop machine with a radeon HD 4850, and on recent kernels
> the radeon driver has failed with the message "No valid linear
> framebuffer address".  lspci on the broken configuration showed the
> first memory region at d0000000 of the radeon card to be ignored.  dmesg
> showed there to be a host bridge window at that address which was also
> ignored.
>
> I haven't quantified "recent" kernel.  I was using the Ubuntu/lucid
> kernels and it broke in the 2.6.32-* timeline, at which point I switched
> to vanilla 2.6.33-rc3 to see if that worked.  I could probably bisect it
> in a day or two when I get a little time.
>
> Following dmesg's instructions, setting pci=use_crs causes the region
> not to be ignored, and my video works again.
>
> I'm attaching a dmesg from the broken & working configurations, lspci
> -vvv output from the working configuration, and the output of acpidump.
>
> (Between the failed/working, I also applied the patch at
> http://bugzilla.kernel.org/show_bug.cgi?id=14954
> to get rid of the ACPI-parsing oops.  But that only fixed the oops.)

[    0.000000] BIOS-provided physical RAM map:
[    0.000000]  BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
[    0.000000]  BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
[    0.000000]  BIOS-e820: 0000000000100000 - 00000000bf790000 (usable)
[    0.000000]  BIOS-e820: 00000000bf790000 - 00000000bf79e000 (ACPI data)
[    0.000000]  BIOS-e820: 00000000bf79e000 - 00000000bf7d0000 (ACPI NVS)
[    0.000000]  BIOS-e820: 00000000bf7d0000 - 00000000bf7e0000 (reserved)
[    0.000000]  BIOS-e820: 00000000bf7ec000 - 00000000c0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[    0.000000]  BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved)
[    0.000000]  BIOS-e820: 0000000100000000 - 0000000340000000 (usable)
...

[    0.833443] PCI: MMCONFIG for domain 0000 [bus 00-ff] at [mem
0xe0000000-0xefffffff] (base 0xe0000000)
[    0.835028] PCI: MMCONFIG at [mem 0xe0000000-0xefffffff] reserved
in ACPI motherboard resources
...

[    0.847449] ACPI: PCI Root Bridge [PCI0] (0000:00)
[    0.847470] pci_root PNP0A08:00: ignoring host bridge windows from
ACPI; boot with "pci=use_crs" to use them
[    0.847693] pci_root PNP0A08:00: host bridge window [io
0x0000-0x0cf7] (ignored)
[    0.847695] pci_root PNP0A08:00: host bridge window [io
0x0d00-0xffff] (ignored)
[    0.847697] pci_root PNP0A08:00: host bridge window [mem
0x000a0000-0x000bffff] (ignored)
[    0.847699] pci_root PNP0A08:00: host bridge window [mem
0x000d0000-0x000dffff] (ignored)
[    0.847701] pci_root PNP0A08:00: host bridge window [mem
0xc0000000-0xdfffffff] (ignored)
[    0.847703] pci_root PNP0A08:00: host bridge window [mem
0xf0000000-0xfed8ffff] (ignored)
...
[    0.848025] IOH bus: [00, fb]
[    0.848026] IOH bus: 00 index 0 io port: [0, ffff]
[    0.848028] IOH bus: 00 index 1 mmio: [e0000000, fdffffff]
...
[    0.849289] PCI: peer root bus 00 res updated from pci conf
...
[    0.849361] pci 0000:04:00.0: reg 10: [mem 0xd0000000-0xdfffffff 64bit pref]
[    0.849369] pci 0000:04:00.0: reg 18: [mem 0xfbee0000-0xfbeeffff 64bit]
[    0.849374] pci 0000:04:00.0: reg 20: [io  0xe000-0xe0ff]
[    0.849381] pci 0000:04:00.0: reg 30: [mem 0xfbec0000-0xfbedffff pref]
[    0.849423] pci 0000:04:00.1: reg 10: [mem 0xfbefc000-0xfbefffff 64bit]
[    0.849481] pci 0000:00:07.0: PCI bridge to [bus 04-04]
[    0.849484] pci 0000:00:07.0:   bridge window [io  0xe000-0xefff]
[    0.849487] pci 0000:00:07.0:   bridge window [mem 0xfbe00000-0xfbefffff]
[    0.849491] pci 0000:00:07.0:   bridge window [mem
0xd0000000-0xdfffffff 64bit pref]


it seems HW IOH only can use [e000000 - fdffffff] under that bridge...

and _CRS said the peer root bus could use [c000000 - dfffffff]

could be that we need to check other register to decide if we can use
reading from ioh reg directly.

YH
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