Messages in this thread | | | Date | Fri, 16 May 2008 09:15:54 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [regression bisected] HR-timers bug >=2.6.25 |
| |
On Thu, 15 May 2008, Justin Madru wrote: > I've reported this problem previously: > http://lkml.org/lkml/2008/3/12/290 > http://bugzilla.kernel.org/show_bug.cgi?id=10235 > https://bugs.freedesktop.org/show_bug.cgi?id=15602 > > This bug is still in mainline as of 2.6.26-rc1. (affected versions 2.6.25-rc0 > - 2.6.26-rc1) > > Ever since 2.6.25-rc3 (the first rc I tested), my screen would blank out when > mode switching from the Ubuntu uplash to the gdm login. Normally after the > boot splash, the screen goes black and "refreshes" to select the correct > resolution. But when using a kernel newer than 2.6.24 the screen doesn't come > back on - it stays blank. This doesn't happen every time, but a good majority > of the time. The workaround is to disable the splash, and that fixes the > problem almost completely. > > I did a git bisect. Rebooting 3 times if the problem didn't occur just to make > sure. > The git bisect reports that it's timing related - which is what Jesse Barnes > said it could be.
Well, it's a timing problem related to splash which is exposed by the scheduler timing changes. This is neither a hrtimer nor a scheduler bug. Something in the splash / video driver switchover relies on some obscure timing which is nowhere guaranteed.
Thanks, tglx
| |