[Intel-gfx] i915 Skylake: "Invalid ROM contents"

[Daniel Stone]

Hi,

On 18 November 2015 at 15:59, Andy Lutomirski <luto at amacapital.net> wrote:
> On Wed, Nov 18, 2015 at 2:59 AM, Ville Syrjälä
> <ville.syrjala at linux.intel.com> wrote:
>> On Tue, Nov 17, 2015 at 11:43:25AM -0800, Andy Lutomirski wrote:
>>> Typing:
>>>
>>> # cat /sys/devices/pci0000:00/0000:00:02.0/rom
>>>
>>> Provokes:
>>>
>>> i915 0000:00:02.0: Invalid ROM contents
>>
>> Hmm. So there's no PCI option ROM there. I wonder what is there. I
>> get the same on my Braswell BTW. I tried to look through the UEFI
>> spec a bit, and it seems to say that even for non-legacy option ROMs
>> the 0x55aa signature should be there.
>>
>> But this being the GPU means we may be using the shadow ROM stuff,
>> which IIRC assumes that the shadow is at 0xc000. I'm not sure that
>> holds anymore with UEFI, and maybe we should be using some UEFI
>> trick instead to find out where it actually lives?
>>
>> BTW what does 'lspci -vv -s 00:02.0' say on your machine?
>>
>
> 00:02.0 VGA compatible controller: Intel Corporation Sky Lake
> Integrated Graphics (rev 07) (prog-if 00 [VGA controller])
>     DeviceName:  Onboard IGD
>     Subsystem: Dell Device 0704
>     Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
> ParErr- Stepping- SERR- FastB2B- DisINTx+
>     Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
> <TAbort- <MAbort- >SERR- <PERR- INTx-
>     Latency: 0
>     Interrupt: pin A routed to IRQ 128
>     Region 0: Memory at db000000 (64-bit, non-prefetchable) [size=16M]
>     Region 2: Memory at 90000000 (64-bit, prefetchable) [size=256M]
>     Region 4: I/O ports at f000 [size=64]
>     Expansion ROM at <unassigned> [disabled]

UEFI has an option to enable option ROMs, which is disabled by
default; I wonder if having it disabled prevents all access to the
ROM.

Mind you, it doesn't seem to be fatal; I've not had any issues with
the same machine that I can pin down to lack of ROM.

Cheers,
Daniel