[git pull] drm fixes

[Linus Torvalds]

On Sun, Nov 29, 2015 at 11:33 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
>
> Yeah I just hunted down a test infrastructure failure on my Haswell the
> past few days with various loads and output configs. Seemed very happy.
> And not aware of anything else blowing up (bdw/skl would be less
> surprising).

So I'm currently suspecting that we may have had a power-brownout
situation. We ended up actually having a complete (but short) power
loss a bit after I saw two consecutive lockup events, and it hasn't
happened since.

I used to have a UPS on the machine, but our power has been stable
enough the last few years that when the battery gave out I just
stopped using it. I guess that next time I rebuild that machine (I'm
planning on upgrading to skylake some time), I'll just make sure to
replace the power supply too. It's probably ten years old by now (the
disks, motherboard and CPU's have all been replaced multiple times,
but the nice silent case and power supply I've just continually
re-used), so I could imagine that a brown-out together with a
weakening power supply might start to be an issue.

                   Linus