Hi,
On 18 November 2015 at 15:59, Andy Lutomirski luto@amacapital.net wrote:
On Wed, Nov 18, 2015 at 2:59 AM, Ville Syrjälä ville.syrjala@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