Bug 43751 - [i915] Error reported trying to load absent Video BIOS
Summary: [i915] Error reported trying to load absent Video BIOS
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: DRI git
Hardware: x86 (IA32) Linux (All)
: lowest normal
Assignee: Chris Wilson
QA Contact:
Depends on:
Reported: 2011-12-12 07:43 UTC by Michael Rieder
Modified: 2017-07-24 23:03 UTC (History)
5 users (show)

See Also:
i915 platform:
i915 features:

Downgrade ERROR message (1.08 KB, patch)
2012-02-24 08:58 UTC, Chris Wilson
no flags Details | Splinter Review

Description Michael Rieder 2011-12-12 07:43:04 UTC
Bug description:

During Boot-Up, I get the following errors in the system log:

kernel: [    1.495711] i915 0000:00:02.0: Invalid ROM contents
kernel: [    1.495768] [drm:intel_parse_bios] *ERROR* VBT signature missing
kernel: [    1.495825] [drm] failed to find VBIOS tables

System runs without problems despite these errors showing up.

System environment:

-- chipset:		945GM/GMS, 943/940GML (not sure which one I got)
-- system architecture:	32-bit
-- kernel:		3.1
-- Linux distribution:	Arch Linux
-- Machine:		Apple Macbook 1,1

Reproducing steps:

Boot in EFI mode, *not* BIOS mode.

Additional info:

I tried to trace where these errors originate and it seems they are caused in i915_load_modeset_init() in linux/drivers/gpu/drm/i915/i915_dma.c when it tries to load the Video ROM (line 1234).

The ROM can't be dumped:
cat: /sys/devices/pci0000:00/0000:00:02.0/rom: Input/output error
Comment 1 Chris Wilson 2011-12-12 08:09:36 UTC
Really this should just be a warning rather than error, since as you found out we can often survive...
Comment 2 Michael Rieder 2011-12-19 04:07:00 UTC
(In reply to comment #1)
> Really this should just be a warning rather than error, since as you found out
> we can often survive...

Out of curiosity: On which systems is the VBIOS needed and on which not?
Comment 3 Chris Wilson 2012-02-24 08:58:57 UTC
Created attachment 57597 [details] [review]
Downgrade ERROR message
Comment 4 Florian Mickler 2012-04-05 06:54:25 UTC
A patch referencing this bug report has been merged in Linux v3.4-rc1:

commit bd45545f7405eab9093da84715f19c6385a57662
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Feb 24 16:53:28 2012 +0000

    drm/i915/bios: Downgrade the "signature missing" DRM_ERROR to debug
Comment 5 Chris Wilson 2012-04-16 05:09:57 UTC
And the error is squelched. Thanks for the bug report.

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