[Intel-gfx] black screen if sna & TearFree

[Chris Wilson]

On Thu, 16 Aug 2012 04:19:26 -0700, Grant <emailgrant at gmail.com> wrote:
> '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?

In the Xorg.log, the first error appears to be a failed modeset after
resume:

[  5131.319] (II) AIGLX: Resuming AIGLX clients after VT switch
[  5131.319] (II) intel(0): switch to mode 1366x768 on crtc 3 (pipe 0)
[  5131.319] (EE) intel(0): failed to set mode: Invalid argument
[  5131.319] (WW) intel(0): failed to restore desired modes on VT switch

That is going to leave the screens blank. And the subsequent segfault
suggests that I don't have sufficient safeguards to handle that failure.
Can you please run 'addr2line -e
/usr/lib64/xorg/modules/drivers/intel_drv.so 0xb9ed7 0x68517 0x5aa2e' ?
To solve what happened to prevent the modeswitch we need to have the
dmesg, preferrably with drm.debug=6 (echo 6 >
/sys/modules/drm/parameters/debug).

Compiling a debug driver is pretty straightforward.
$ git clone git://anongit.freedesktop.org/xorg/driver/xf86-video-intel
$ cd xf86-video-intel
$ ./autogen.sh --prefix=/usr --enable-debug=full
$ make && sudo make install

This will overwrite the system driver and so not need any modification
to config files. (It is possible to install into local and change
/etc/X11/xorg.conf to load the driver from there.) So just reinstall
your distro package to revert.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre