Re: [PATCH] Fix i915 drm regression on AOpen i915GMm-HFS motherboard

From: Knut Petersen
Date: Mon Jan 03 2011 - 18:10:02 EST

Am 03.01.2011 20:59, schrieb Chris Wilson:

So I did some additional compiles and tests. The distribution used is
openSuSE 11.3.

openSuSE 11.3 kernel
System locks up while starting X, hard reset is needed.


VGA and DVI connectors do work as expected.
xrandr shows VGA1, DVI1, TV1 and TV2. Thats correct, these are the
present on the i915GMm-HFS mobo. But read from boot.msg:

agpgart-intel 0000:00:00.0: Intel 915GM Chipset
agpgart-intel 0000:00:00.0: detected 7932K stolen memory
agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xc0000000
[drm] Initialized drm 1.1.0 20060810
i915 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
i915 0000:00:02.0: setting latency timer to 64
[i915_sdvo:intel_sdvo_init], SDVOB device VID/DID: 02:3C.06, clock range
25MHz - 200MHz, input 1: Y, input 2: N, output 1: Y, output 2: N
[i915_sdvo:intel_sdvo_init], SDVOC device VID/DID: 02:C2.01, clock range
25MHz - 166MHz, input 1: Y, input 2: N, output 1: Y, output 2: N
[drm] TV-12: set mode NTSC 480i 0
render error detected, EIR: 0x00000010
page table error
PGTBL_ER: 0x00000010
[drm:i915_handle_error] *ERROR* EIR stuck: 0x00000010, masking
render error detected, EIR: 0x00000010
page table error
PGTBL_ER: 0x00000010
[drm] DAC-6: set mode 1280x1024 2c
[drm] TMDS-8: set mode 1280x1024 2d
Console: switching to colour frame buffer device 160x64
[drm] fb0: inteldrmfb frame buffer device
[drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0

Kernel 2.6.37-rc8-git2

text mode console: ok, resolution 1280x1024, fully used by framebuffer
X: first device detected is LVDS with resolution 1024x768. VGA and DVI
connector work in X,
but X switches to 1024x768 for both of them. xrandr reports the four
physical connectors but
also LVDS, VGA2 and TV3 connectors.

Kernel 2.6.37-rc8-git2 + patch Chris Wilson

VGA connector broken for both framebuffer console and X. No signal,
monitor switches off. xrandr does
not report the connected monitor.

DVI connector does work, but: physical resolution for framebuffer
console is 1280x1024, text output
is done on the top left 1024x768. X switches to 1024x768 resolution ;-(

LVDS, VGA2 and TV3 reported by xrandr although these are not present.

Kernel 2.6.37-rc8-git2 + patch Knut Petersen
Both VGA and DVI connectors work as expected, monitor is correctly
framebuffer console and X use maximum possible resolution. No page table
as in LVDS does not show up in xrandr output, but VGA2 and
TV3 are
still detected.

Kernel 2.6.37-rc8-git2 + patches Knut Petersen and Chris Wilson
no difference to 2.6.37-rc8-git2 + patch Knut Petersen

With my patch I do cure the symptoms for at least the and
2.6.37-rc8-git2 kernels.
Maybe that's the right thing to do now, but if someone could cure the
real cause of the problem it
would be an even better idea.


> On Mon, 3 Jan 2011 11:45:48 -0800, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>> On Mon, Jan 3, 2011 at 10:12 AM, Knut Petersen
>> <Knut_Petersen@xxxxxxxxxxx> wrote:
>>> I tried 2.6.37-rc8-git2 with both patches applied.
>> I thought Chris meant "instead of", rather than "both". Chris?
> Right, I was trying to ascertain whether the intel_lvds_ddc_probe()
> correctly detected the missing panel. That function currently requires
> GMBUS to differentiate between a NAK and an IO error (bitbanging just
> returns EREMOTEIO regardless, iirc). So far it has been successful in
> detecting one false-positive for an AOpen All-in-one and hasn't fouled
> up LVDS detection for the laptops I have.
> -Chris

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