On Mon, Mar 30, 2009 at 06:52:50AM -0000, Amit Kucheria wrote: > On Sun, Mar 29, 2009 at 11:55 PM, Bryce Harrington > <br...@bryceharrington.org> wrote: > > > Meanwhile, regarding the ring error, I don't know of troubleshooting > > techniques for this class of issue, other than forwarding it upstream. > > What I think they will require is to have the specific steps to > > reproduce the issue. Can you try repeating the steps you described and > > see if you can reproduce the failure a couple times? > > What is the ring buffer and how is it used by the driver?
I don't know if there is documentation explaining what it is. I've just sort of pieced guesses together and am probably wrong, but I've assumed it is a circular link list data structure containing memory buffer objects that the video driver uses for some purpose. From what I've gathered, this data structure isn't the *cause* of the bug, just that when certain kinds of bugs occur, part of the error dump includes dumping the state in the ring buffer. Unfortunately, not much beyond this dump is provided with this class of error, so they're hard to troubleshoot. I don't know how to make heads or tails out of the ring dump (pun, sorry) and in talking with upstream they've suggested not bothering to try to do so, as it isn't sufficient for figuring out the issue. > If we know what it is, I could try to concentrate on reproducing my > actions to stress that part of the HW. > > I am not able to reproduce the bug just by having many Firefox tabs > and going to graphics intensive websites. So that might be a red > herring. The bugs associated with web pages often are hard to reproduce and seem to depend on seemingly random conditions. Sometimes I wonder if they're dependent on filling up certain buffers in certain ways before triggering them. I.e., if you do ABC after a fresh boot you can't reproduce it, but if you then do ABC after the system's been up and in use for a couple days, then *pow* it always does it. On -psb with somewhat similar issues, we found that reducing some of the memory parameters for the driver would make bugs more easily reproduced. Browsing through 'man intel' there's a few parameters for controlling video memory, however from the descriptions they don't appear to be quite what we need. ulimit -m and booting with reduced overall memory via mem= could be other options. Bryce -- Ring buffer not flushed - X server crashes and switches to low-res mode https://bugs.launchpad.net/bugs/351187 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
