Bug#525619: xserver-xorg-video-intel: screen blank after returning to vt7

[Sanjoy Mahajan <sanjoy@olin.edu>]

> could we please get an update, with either squeeze or higher?

Alas, yes: I still see the problem.  It happens every couple days where
the screen is blank (but the backlight is on).  A few days ago I had
started filling out a new Debian bug report, but then got the hang
again, rebooted, and lost track of the report -- which I just found and
am appending the version info from it.

When the problem happens, the backlight is on but the screen is blank,
and I can do everything except see what is on the screen -- so I can
switch to vt1, log in as root, and cleanly reboot.  However, I found
nothing interesting in any of the log files, whether Xorg.0.log, the
syslog, xdm.log, or /var/log/messages.

Since then I've added "drm.debug=14 log_buf_len=16M" to all grub
boot-command lines (copied from a Fedora "debugging X" page).  I've also
prepared a script to run (typing blind and loggin in as root) when the
problem next happens in order to get more debugging info:

  d=/root/debug-blank-display
  mkdir -p $d
  dmesg > $d/dmesg.log
  cp -p /var/log/Xorg.0.log $d/
  mount -t debugfs none /sys/kernel/debug
  dd if=/dev/mem of=$d/gpu_rom.dd bs=64k skip=12 count=1
  intel_gpu_dump > $d/gpu_dump.log

Anything to add or subtract from that script?

And here's what was in the half-finished bug report from Feb 20:

Package: xserver-xorg-video-intel
Version: 2:2.14.0-4
Severity: normal

Every few days (so perhaps ten S3 suspend/resume cycles) the following
happens.  

-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 2.6.37 (SMP w/2 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages xserver-xorg-video-intel depends on:
ii  libc6                         2.11.2-11  Embedded GNU C Library: Shared lib
ii  libdrm-intel1                 2.4.23-3   Userspace interface to intel-speci
ii  libdrm2                       2.4.23-3   Userspace interface to kernel DRM 
ii  libpciaccess0                 0.12.1-1   Generic PCI access library for X
ii  libudev0                      166-1      libudev shared library
ii  libx11-6                      2:1.4.1-4  X11 client-side library
ii  libx11-xcb1                   2:1.4.1-4  Xlib/XCB interface library
ii  libxcb-aux0                   0.3.6-1    utility libraries for X C Binding 
ii  libxcb-dri2-0                 1.7-2      X C Binding, dri2 extension
ii  libxcb1                       1.7-2      X C Binding
ii  libxext6                      2:1.2.0-2  X11 miscellaneous extension librar
ii  libxfixes3                    1:4.0.5-1  X11 miscellaneous 'fixes' extensio
ii  libxv1                        2:1.0.6-1  X11 Video extension library
ii  libxvmc1                      2:1.0.6-1  X11 Video extension library
ii  xserver-xorg-core [xorg-video 2:1.9.4-2  Xorg X server - core server