Debugging hang on resume from STR?

[Karl Tomlinson]

Jani Monoses writes:

> In a dual monitor setup on a laptop with the card
>
> 01:00.0 VGA compatible controller: ATI Technologies Inc M24 1P
> [Radeon Mobility X600]
> ( 01:00.0 0300: 1002:3150 )
>
> on resuming from suspend to RAM the machine locks up, no pings, no
> caps-lock toggling, blank screen.

See
http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.35.y.git;a=blob;f=Documentation/power/s2ram.txt;h=514b94fc931e09b337fd297401d9f9c1aa391dac;hb=HEAD
for info on TRACE_RESUME, which
can be used to determine how far resume process gets.

I was hitting a similar issue in
https://bugzilla.kernel.org/show_bug.cgi?id=17692
so you may like to try disabling ColorTiling.