[Intel-gfx] black screen if sna & TearFree

[Grant]

>> > I'm using a Dell XPS 13 laptop on Gentoo and if I use:
>> >
>> > Option "AccelMethod" "sna"
>> > Option "TearFree" "true"
>> >
>> > my video tearing problem disappears, but if I close my laptop lid for
>> > a few minutes, it comes back up with a black screen, although I can
>> > get my session back if I switch to VT1 and then back to VT7.  I can't
>> > find anything in the logs.  I've tried xf86-video-intel-2.20.3 as well
>> > as the latest from git.  The problem doesn't occur without the above
>> > two directives.
>> >
>> > Does anyone know how to diagnose or fix this?
>> >
>> > - Grant
>>
>> I can prevent this if I issue 'xset -dpms' before closing the laptop
>> lid, but xlockmore automatically re-enables dpms unfortunately.  BTW,
>> this does not prevent the problem:
>
> The implication would seem to be that an action during dpms is going
> wrong. Does a simple 'xset dpms force off; sleep 1; xset dpms force on'
> trigger the error? If so can you please attach your Xorg.0.log and if
> you could compile with --enable-debug=full and send me the log
> reproducing the error that would be very helpful.
>
> Thanks,
> -Chris

'xset dpms force off; sleep 1; xset dpms force on' does indeed trigger
the error.  I've attached my Xorg.0.log.old which includes the
segfault backtrace.  I'm like a newborn baby when it comes to
compiling and Gentoo doesn't have a debug USE flag for
xf86-video-intel or xorg-server so I can't help there.  Is there a
different package I should check for a debug USE flag?

- Grant