Re: Intel graphics CPU usage - SDVO detect bogosity?
From: Linus Torvalds
Date: Mon Aug 16 2010 - 00:27:57 EST
On Sun, Aug 15, 2010 at 9:06 PM, Andy Lutomirski <luto@xxxxxxxxxxxxx> wrote:
>
> You might be hitting the infamous hotplug storm [1]. The symptoms vary by
> kernel version.
Hmm. I don't think it's a storm. The drm.debug=4 thing shows things
just every 10 seconds. That seems pretty controlled.
Of course, it seems to be several milliseconds worth of work then, so
it's not _too_ controlled. I must be missing some detail.
> If I'm right, the outputs of intel_bios_dumper and intel_bios_reader could
> be instructive (both are in intel-gpu-tools).
My version of intel-gpu-tools must be old (fedora 12). It has
intel_gpu_dump and intel_reg_write and some other apps, but not the
bios-dumper/reader.
Not that I could read the output of them anyway, I bet ;)
> You could also try intel_reg_write 0x61110 0x0 and see if the problem stops
> (at least until a suspend/resume cycle). That command turns off output
> hotplug on the card, which has the side effect that the kernel will stop
> acting on bogus interrupts.
# intel_reg_write 0x61110 0x0
Value before: 0x4000220
Value after: 0x0
but it doesn't seem to change any behavior. Still that sdvo probe
every 10 s, and still 1% of CPU for kworker in top. But that kworker
thing definitely has to be separate from the 10-second sdvo probe,
because it shows up all the time (ie top updates every second).
But right now the wife is using that machine, so I can't check the "it
should be totally idle, what the heck is going on" behavior at the
moment.
Linus
Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/