I'm seeing several issues related to the radeon driver on a MacBook Pro 8,2 with the following graphics card:
ATI Technologies Inc Whistler [AMD Radeon HD 6600M Series] [1002:6741]
All problems were observed when using kernel version 3.2.1. None are seen when using fglrx.
1. Excessive power draw. When using the radeon driver ACPI reports a power draw of about 30W on an idle desktop. Using fglrx brings this number down to 15W.
2. Occasional long delays when suspending. When this happens I see messages like following in dmesg:
[drm:atom_op_jump] *ERROR* atombios stuck in loop for more than 5secs aborting [drm:atom_execute_table_locked] *ERROR* atombios stuck executing D44E (len 62, WS 0, PS 0) @ 0xD46A
Sometimes one of suspend or resume hangs completely, but I can't tell which and am not sure whether or not it's related. I'm also testing a Mac Mini with the exact same card which does not seem to suffer from this issue.
I ran a bisections that identified f8d0edd (drm/radeon/kms: improve DP detect logic) as introducing problems with suspend, and reverting this patch on top of 3.2.1 does seem to eliminate both issues.
3. When the LVDS panel is powered off and back on, the display flickers, as if the backlight is cycling rapidly between low and high brightness. If the panel is left on this effect gradually lessens and is eventually no longer noticable. This is not seen with fglrx.
Thanks, Seth