[Intel-gfx] Macbook Air 6, 2: i915-related interrupt storm after Yosemite update -- resolved

[Christian Kastner]

On 2014-11-01 18:08, Christian Kastner wrote:
> I have a Macbook Air (2013) (6,2) which until recently was working
> flawlessly with Debian unstable, which I use almost exclusively on that
> machine. I did keep the OSX installation, mainly because it's the only
> way to get firmware updates.
> 
> Recently, in a moment of weakness, I said "yes" to the offer of
> upgrading OSX to Yosemite. Since then, whenever I boot Debian, there is
> an i915-related interrupt storm, with a kworker thread constantly
> running at 70%.
> 
> Downgrading OSX back to Mavericks did not help. Apparently Yosemite
> included firmware updates, as within OSX I am shown version numbers that
> are so new they aren't even listed on Apple's homepage yet.
> 
> Here's what I see:
> 
>   $ GPE=/sys/firmware/acpi/interrupts/gpe66
>   $ while true; doe cat $GPE; sleep 1; done
>   727268   enabled
>   757981   enabled
>   788576   enabled
>   807337   enabled
>   828426   enabled
>         ...
> 
> I've tested this with 3.16 and 3.17 kernels; I was using the former for
> about a month now without issue.
> 
> When I boot with modprobe.blacklist=i915, the issue disappears.
> 
> Does anyone have an idea what could be going on?

Good news: the recent update of OSX to 10.10.2 contained another silent
firmware update, and it appears that this update resolved the issue.

Regards,
Christian