Re: Linux 2.6.35-rc2

From: Alex Deucher
Date: Mon Jun 07 2010 - 01:59:12 EST


On Sun, Jun 6, 2010 at 11:04 AM, Torsten Kaiser
<just.for.lkml@xxxxxxxxxxxxxx> wrote:
> [CC:Jeff+Tejun not removed, because you might want to look at the
> attached dmesgs]
>
> On Sun, Jun 6, 2010 at 4:19 PM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>> On Sun, 6 Jun 2010, Torsten Kaiser wrote:
>>>
>>> The first problem that shows up is, that after the KMS switches to the
>>> correct video mode (1280x1024 for an DVI attached LCD), the display
>>> begins to flicker. Every 1..2 seconds (guesstimated) the display turns
>>> off and on again. Something in the new powersaving?
>>
>> Or maybe a borderline display timing that the display has trouble syncing
>> up with?
>
> With 2.6.34 and any previous KMS kernels the output was always stable.
> (I think, I switch to the radeon KMS on 2.6.32)
> The onscreen menu of the monitor showed 1280x1024@xxxxxx for
> 2.6.35-rc2, if I recall correctly.
> Now back on 2.6.34 its 1280x1024@xxxxxxx

The pm code shouldn't have any affect as your system only has one
power state, so it never kicks in. It sounds like a display pll
problem, but there haven't been any changes to that code since 2.6.34.
Any chance you could bisect it?

>
> Comparing the DRM output from 2.6.34 and 2.6.35-rc2 I see the
> following differences:
> On 2.6.35-rc2 this block is missing:
> [    1.907716] [drm] GPU reset succeed (RBBM_STATUS=0x00000140)
> [    1.913403] [drm] 1 Power State(s)
> [    1.916810] [drm] State 0 Default (default)
> [    1.921017] [drm]    16 PCIE Lanes
> [    1.924255] [drm]    1 Clock Mode(s)
> [    1.927662] [drm]            0 engine/memory: 325000/200000
> [    1.932496] [drm] radeon: power management initialized
> New on 2.6.35: [    1.951340] [TTM] Initializing pool allocator.
> Only on 2.6.34: [    2.011963] [drm] radeon: cp idle (0x10000C03)
> Only on 2.6.34: [    2.020478] platform radeon_cp.0: firmware: using
> built-in firmware radeon/R300_cp.bin
>
> On 2.6.34 the output for connector 1 is:
> [    2.090935] [drm] Connector 1:
> [    2.094002] [drm]   DVI-I
> [    2.096629] [drm]   HPD1
> [    2.099174] [drm]   DDC: 0x64 0x64 0x64 0x64 0x64 0x64 0x64 0x64
> [    2.105210] [drm]   Encoders:
> [    2.108189] [drm]     CRT2: INTERNAL_DAC2
> [    2.112222] [drm]     DFP1: INTERNAL_TMDS1
> With 2.6.35-rc2 the line 'HPD1' switches to 'NONE'
>

Whoops. that's a typo in the print out. I'll send Dave a patch to fix that.

Alex

> Everything else is identical. I have attached complete dmesg from both
> kernels to this mail.
>
> Torsten
>
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