Comment 63 for bug 719620

Hi,

I prepared a new kernel with debugging for you to test, 2.6.38-6.33~lp719620r4

To test it, please add log_buf_len=1M kernel parameter to the kernel command line in grub, then install the kernel (for example edit /etc/default/grub and append log_buf_len=1M to GRUB_CMDLINE_LINUX_DEFAULT). As there will be extra debug output we have to increase the log size, 1M I think will be sufficient.

Then boot the kernel, perform the suspend & resume 2 times as you did before, and attach here the dmesg output.

After this, turn off the machine to restart the test, and do same test, but before you do the 2 suspend & resumes, please enable old_resume parameter I create for some extra debug:
sudo sh -c "echo Y > /sys/module/video/parameters/old_resume"
And do the test, and attach this second dmesg output.

I hope with this extra debug to check exactly more of what's happening for the bug to happen.

For a third test, and before you start the test, please enable ssh server on the machine. Then when the machine resumes and the screen is black, please try login into the machine with ssh and change the brightness writing to /sys/class/backlight/acpi_video0/brightness (see max_brightness on same directory to check what is the max value supported). Please tell if the screen remains black or not with this third test.