On Mon, 2014-12-15 at 16:11 -0500, Valdis.Kletnieks@vt.edu wrote:
On Mon, 15 Dec 2014 14:19:32 -0600, Chris said:
On Mon, 2014-12-15 at 13:43 -0500, Valdis.Kletnieks@vt.edu wrote:
I'm pretty sure that's a timer for the i915 driver that detects if the GPU has gone into an infinite loop due to (usually) buggy programming from the operating system....
Thank you Valdis as far as the OS we're talking about Ubuntu not the bios correct?
More specifically, the i915 is actually a fully programmable CPU in its own right, but it's a crazy morass of interrupts and circular buggers and race conditions. The operating system (Ubuntu or what have you) actually send the i915 a program of what to display, and the i915 goes off and does it. Of course, missing a single interrupt or an off-by-one error in a circular buffer will cause the i915 to go off the rails and usually get hung in a hard loop.
(It doesn't help that the i915 has a ton of wonky restrictions of the form "you can do this during a vertical retrace period, but only during the first half of a horizontal retrace". And yes, I'm pretty sure it actually enforces vertical and horizontal retrace timings on LCDs. Silly, huh? ;)
I believe I understand Valdis, what kind of actions would need to be taken to track this down, if it's possible, or to simply fix the problem once and for all? -- Chris KeyID 0xE372A7DA98E6705C 31.11°N 97.89°W (Elev. 1092 ft) 15:16:18 up 3:21, 3 users, load average: 0.17, 0.19, 0.18 Ubuntu 14.04.1 LTS, kernel 3.13.0-43-generic