Created attachment 24328 [details] dmesg segment before problems start I'm on an Acer Timeline 4810TZ-4658, Intel GMA 4500MHD. SO is Gentoo and video driver is intel i915 provided by xf86-video-intel-2.9.1. When I start the computer, everything works fine but, if I press the bright keys on my keyboard, my video becomes very slowly and the best I can do is restart it and start to use it in a full backlight mode. Here, I sent a part of my dmesg output when it is all ok and a part where it is not. Thanks in advance, Daniel
Correcting, there are just a single attachment, because both are equals. Sorry.
*** Bug 14917 has been marked as a duplicate of this bug. ***
Looks like an ACPI issue to me.
Suggestions to search?
You could try using the 'perf' tool to see where in the kernel your hotkeys are spending time. I'd guess it's somewhere in the ACPI code; it's probably waiting for a platform method to return.
Hi Jesse. I'm a little bit confused about how can I use 'perf' to see that. Could you help me? When I use # perf top I notice that read_hpet is about 65%. Is it normal? Thanks a lot.
Probably, that's where the timer code ends up, which gets called whenever timers expire afaik. Maybe the ACPI developers have a better way of seeing how long method invocation takes. Yakui?
Hi all. It is solved! What happened was that I enabled "HPET Timer support" on "Processor type and features". The help page say that it will be enabled only if BIOS and the plataform support it but it seems to be wrong. I do not have this support and it someway was lagging my system. Once I disable it, it solve my problem. I have disable the "High Resolution Timer Support" too, because I do not have hardware to deal with it. Disabling both seems to be the best configuration for this problem. Thanks a lot Jesse for your guide.
I am thinking about this. Could it be a bug? Since I have not support for these features, should them harm my system? According to help pages, not.