DRM/I915 wrong monitor resolution

[Alexandre Felipe Muller de Souza <alexandrefm@mandriva.com.br>]

Hi all,
We encountered a lot of X problems with current Kernel in this specific
hardware:

00:02.0 VGA compatible controller: Intel Corporation Pineview Integrated
Graphics Controller (rev 02) (prog-if 00 [VGA controller])
        Subsystem: Elitegroup Computer Systems Device 2267
        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 43
        Region 0: Memory at feb00000 (32-bit, non-prefetchable)
[size=512K]
        Region 1: I/O ports at dc00 [size=8]
        Region 2: Memory at d0000000 (32-bit, prefetchable) [size=256M]
        Region 3: Memory at fea00000 (32-bit, non-prefetchable)
[size=1M]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: <access denied>
        Kernel driver in use: i915
        Kernel modules: i915

The xrandr shows 2 monitors, when only exists 1 (the device even doesn't
have HDMI or TV). The X also can use only bad resolutions for the main
monitor.

I tested <= 2.6.36 kernel and it was ok, and kernel >= 2.6.37 was not
ok.

So, I made a git bisect to discover exactly what commit broked the
driver and I made a fix reverting the commit:
44834a67c0082e2cf74b16be91e4910
Description:
drm/i915: Use the VBT from OpRegion when available (v3)

I think it will be bad to maintain the patch in our kernel, and rediff
it every time we made a kernel update. So I decided to report it, to
know if someone knows how to maintain the commit and fix the problem.

Or it could be a bad (with bugs) hardware?


Thanks a lot
Alexandre