[Nouveau] GeForce 6100 (NV4E) & nouveau regression in 3.12

[Ilia Mirkin]

On Mon, Feb 10, 2014 at 10:12 AM, Rafał Miłecki <zajec5 at gmail.com> wrote:
> 2014-02-09 23:12 GMT+01:00 Ilia Mirkin <imirkin at alum.mit.edu>:
>> On Sun, Feb 9, 2014 at 5:08 PM, Rafał Miłecki <zajec5 at gmail.com> wrote:
>>> Last week I've switched from my old & good 3.4.63 to 3.14-rc1 and
>>> noticed nasty display corruptions when using nouveau. It seems that
>>> changing parts of the screen are appearing for a fraction of second in
>>> random places. I've recorded this behavior:
>>> http://www.youtube.com/watch?v=IEq7JzGVzj0
>>>
>>> My hardware is some old motherboard with
>>> 00:05.0 VGA compatible controller [0300]: NVIDIA Corporation C51G
>>> [GeForce 6100] [10de:0242] (rev a2)
>>> integrated. Since my CPU is ancient AMD Sempron(tm) Processor 2800+ it
>>> took me few days to track this issue.
>>>
>>> There goes some summary of various kernels:
>>>
>>> 1) 3.4.63
>>> No display problems. Works great.
>>>
>>> 2) commit 928c2f0c006bf7f381f58af2b2786d2a858ae311
>>> drm/fb-helper: don't sleep for screen unblank when an oops is in progress
>>> Scrollbars have a pink line. I didn't track which commit introduced
>>> this pink corruption. No other problems.
>>>
>>> 3) commit c21eb21cb50d58e7cbdcb8b9e7ff68b85cfa5095
>>> Revert "drm: mark context support as a legacy subsystem"
>>> This fixes pink lines on scrollbars and introduces this nasty display
>>> corruption. It's one commit after previous one.
>>> It means it's the first bad commit for these nasty corruptions recoded
>>> and uploaded to YouTube.
>>>
>>> 4) 3.14-rc1
>>> No changes since c21eb21cb50d58e7cbdcb8b9e7ff68b85cfa5095. No pink
>>> lines, but display corruptions happening.
>>
>> Can you boot with nouveau.config=NvMSI=0 ? If that helps, there are
>> some patches on the nouveau/dri-devel lists (search for "nv4c") that
>> may help you.
>
> Unfortunately this config parameter doesn't help :(

Too bad. It may still be worthwhile applying the patches and seeing
what happens... it seems like some registers got switched around on
the nv4x IGP's:

http://lists.freedesktop.org/archives/nouveau/2014-February/016032.html
http://lists.freedesktop.org/archives/nouveau/2014-February/016033.html
http://lists.freedesktop.org/archives/nouveau/2014-February/016034.html

BTW, youtube says "this video is unavailable".

Is there anything in dmesg when the display corruptions happen?

There was also an issue with libdrm_nouveau for pre-nv50 chips, when
compiled with gcc-4.8 some time back... fixed in... 2.4.48 or so?

Lastly, it may be worth trying 3.11.x and 3.12.x to get a better
handle on when problems happened. The commits you cite are in the
middle of releases, and may have various badness associated with them
(e.g. 3.12-rc had a later-disabled MSI implementation, back in 3.13...
probably some other stuff).

  -ilia