https://bugzilla.kernel.org/show_bug.cgi?id=34772
--- Comment #9 from Rogério Brito rbrito@ime.usp.br 2011-05-21 09:16:28 --- Hi, Michel.
On Fri, May 20, 2011 at 12:11, bugzilla-daemon@bugzilla.kernel.org wrote:
--- Comment #6 from Michel Dänzer michel@daenzer.net 2011-05-20 12:11:38 --- (In reply to comment #1)
Anyway, things are *way* better with 2.6.38 than with 2.6.39, as with 2.6.39 the kernel doesn't even get the colors correctly---everything that should be red becomes blue and so forth (any kind of endianness problem?).
That's probably nothing to do with the kernel directly but endianness bugs in the X driver when acceleration is not available.
OK, then that's a separate issue. Good to know.
It would be interesting if you could bisect what broke acceleration with radeon.agpmode=-1.
Oooh, I guess that I made some mess in your head here, taking into account the other messages of us. To clear things up: When I use 2.6.38, it works mostly OK if I use radeon.agpmode=-1. It is sufficiently stable to the point that I told you that this setting was OK. But, in fact, if I play a video with mplayer, then it always (so far, 100% reproducible) causes those GPU lockups, but the computer is still accessible via the network, so that I can take the logs etc. If, instead, I use 1 instead of -1, then, even with kernel 2.6.38, I get those lysergide-like :-) pictures that I put on my homepage (but, for documentation purposes, I am thinking of uploading here as attachments, as I am quite short of space there).
With kernel 2.6.39, I have not been able to get anything working, whether or not I pass any option to the kernel.
Summary:
* 2.6.38 with KMS and agpmode=-1: OK, up to me trying to play some video, then GPU lockups. * 2.6.38 with KMS and agpmode=1: GPU lockups a few seconds after X loads (it *does* show up, but locks up a few seconds latter). * 2.6.39 with KMS and agpmode=-1: Not OK, even if I don't use anything accelerated (problems with colors and software rendering).
So, I am not quite sure if it would be the case of bisecting or, at least, what would be a good starting point. I can, though, try to boot with many other kernels to see if I can (provided that udev doesn't stop me).
Note that you should boot with radeon.no_wb=1 as well for
OK. I can try no_wb=1 with agpmode=-1 and report back in a few moments, to see if the lockups are still there or not.
this, as CP writeback was only fixed during the 2.6.39 cycle (in commit dc66b325f161bb651493c7d96ad44876b629cf6a).
Right. Thanks for that fix of yours (just read the commit).
Regards,