i915 DRM problems in lucid.

[Chase Douglas]

Hi Robert,

On Sat, Mar 27, 2010 at 12:15 PM, Robert Hooker <sarvatt at ubuntu.com> wrote:
> Hello, I've found a lot of bug fixes for i915 that seem needed in the
> lucid kernel and I thought I'd list them here for consideration since
> I'm not having any luck in IRC.

Sorry to hear that. We do try to pay attention to #ubuntu-kernel, but
sometimes stuff slips through when we get busy. Of course, email's
great for making sure we at least see things :).

> * GPU hangs after DPMS events
> *Quite* a lot of reports of this bug, the fix was included in
> 2.6.32-15 but was dropped during the 2.6.33 DRM merge that happened in
> 2.6.32-16. Due to the number of people it affects it seems pretty
> urgent to bring this back in. Symptoms include hangs after lid close,
> idle screen blanking, and suspend/resume. dmesg and old xorg/gdm logs
> will show batchbuffer I/O errors when it crashed, EIR is always
> 00000000 and it eventually ends up with an assert like this happening
> - X: ../../src/i830_batchbuffer.h:79: intel_batch_emit_dword:
> Assertion `pI830->batch_ptr != ((void *)0)' failed.
>
> Bug: https://launchpad.net/bugs/535640
> Fix: http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-lucid.git;a=commit;h=7b56712ff524ee55e38afaee3954d125f56a6070

Unfortunately, the patch was merged into -16 with the .33 drm
backport. You can find it at:

http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-lucid.git;a=commitdiff;h=bd53bbe184ca00326a3c21834f41cca7a7bdb6d4#patch44

It's a huge commit diff, but if you search for the function,
intel_release_load_detect_pipe, you'll find that the patch still
exists. So it seems the fix lies elsewhere...

> * Framebuffer compression causing rendering to stop on 915 and 945
> mobile devices after resume.
> This one was brought up on the list previously, but it is pretty nasty
> and affects all mobile 915-945 users. I submitted my patch upstream
> and they applied it and I will send it to stable once it's in linus'
> tree but that will probably be awhile with how rarely the intel tree
> is pulled in lately.
>
> Bug: https://bugs.edge.launchpad.net/ubuntu/+source/linux/+bug/492392
> Fix: https://patchwork.kernel.org/patch/86999/

I remember hearing about this on irc, and I think Andy was looking at
it. He's been off this past week, but I think he'll be back Monday. It
might not hurt to ping him about it, but I'm pretty sure it'll be
committed shortly assuming there weren't any ill effects.

> * i915 module getting loaded before agpgart
> This has been an issue since karmic at least, and is also happening
> with radeon. Intel has fixed this in 2.6.34 but it hasn't been
> backported to stable yet. This especially seems like a backport worth
> considering due to how fast boots are now. Side note about this:
> upstream might even actually require AGP modules to be built into the
> kernel at some point, the consensus seems to be module AGP=bad.
>
> Bug: https://bugs.launchpad.net/bugs/542251
> Fix: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1f7a6e372e9cb4d749f34c0738d832e6cadb4071

This seems reasonable to me. See my notes below about the next step for this.

> * Large number of reports requiring lid quirks
> Upstream has decided to drop the requirement of having a lid open
> status to enable the LVDS completely because a large number of quirks
> were getting sent, a lot of manufacturers screw this up because
> Windows/OSX don't require it.
>
> Fix: http://git.kernel.org/?p=linux/kernel/git/anholt/drm-intel.git;a=commit;h=6e6c822868f113dabe3c33bdd91e883cc28fa11b

I remember this being discussed recently, but I can't remember where.
It's probably on someone's radar.

In general, if you have specific fixes the best thing to do is follow
the instructions on the wiki [1]. When you send a patch it gets queued
up at [2]. This list is monitored by the release maintainers to ensure
that we haven't missed anything.

I hope this helps,
Chase

[1] https://wiki.ubuntu.com/KernelTeam/KernelBugFixing
[2] http://patchwork.ozlabs.org/project/ubuntu-kernel/list/