Created attachment 97496 [details]
dmesg with dri.debug=4

I have a behaviour very similar to
https://bugs.freedesktop.org/show_bug.cgi?id=42960.

After resuming from suspend, display is blank.

I have tried the tricks suggested in #42960 (acpi_sleep=s3_bios) with no luck,
when I use that the laptop doesn't resume correctly.

With the catalyst driver the display resumes correctly. 

It's an Ubuntu 13.10 with a 3.14 kernel, DPM is activated.

Feel free to ask for tests.