Hi, On 05/02/2014 07:03 PM, Tibor Billes wrote: > Hi, > > I've upgraded my 3.13.5 kernel to 3.14.2 and I noticed that sometimes my > mouse is slow to react. > By slow I mean the pointer on the screen doesn't follow its path smoothly, > instead it jumps from one > position to the next at only a few jumps per second rate. Like if the kernel > could only process 2 or 3 > position updates per second from the mouse. (As far as I can tell, the > machine is in idle.) > After experimenting a little I found out that the keyboard is also affected. > Keystrokes are delayed, > letters appearing in bursts. This behaviour (for both the mouse and the > keyboard) lasts only for a > couple of seconds, then it suddenly goes away and everything works as > expected. I also noticed that > this behaviour shows up after I haven't touched the mouse or the keyboard for > short time (around > 10 seconds, but I didn't measure this).
What I think is happening is that you've auto screen dimming on inactivity enabled in your desktop environment settings, which results in trying to change the backlight after 10 seconds of inactivity. Then the intel video driver likely directly writes to /sys/class/backlight/acpi_video0/brightness and gets stuck in that write because the acpi code gets stuck. I've seen this happen occasionally on my E6430 both with and without the patch the bisect points too. I can trigger it by pressing brightness up / down as fast as I can. Likely the dimming on inactivity code is doing a much better job at sending brightness change commands as fast as possible, making it easier to trigger this. As for the commit you've bisected it too, it may be that that subtly changes things to make the problem easier to trigger, but I distinctly remember having the same issue before I wrote that patch. Have you tried updating your BIOS ? Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
