Created attachment 62612 [details]
syslog from suspend/resume cycle
When resuming from suspend-to-ram on a HP DV6 3167-ca laptop, the display does not come back to life, although everything else seems to work - I can type blind and reboot the machine etc.
This laptop has two radeon cards:
$ lspci -vnn |grep VGA
01:05.0 VGA compatible controller : ATI Technologies Inc M880G [Mobility Radeon HD 4200] [1002:9712] (prog-if 00 [VGA controller])
02:00.0 VGA compatible controller : ATI Technologies Inc Redwood [Radeon HD 5600 Series] [1002:68c1] (rev ff) (prog-if ff)
vgaswitcheroo works as expected and the power settings in /.../vgaswitcheroo/switch do not affect the outcome (i.e. display dead after resume). The suspend is done when running on the 4200 series card.
I am attaching a syslog. The line
kernel: [ 191.930153] radeon 0000:02:00.0: Refused to change power state, currently in D3
appears to be the smoking gun. This is on Ubuntu Natty, which runs a kernel based on 2.6.38. However, Chris (who I'm including on this bug) has the same type of laptop. He has tried with various mainline kernels, including 3.0-rc kernels and gets the same result. Also, he said resume *does* work with the latest ATI proprietary driver.
As a test, I tried doing
# echo core > /sys/power/pm_test
# echo mem >/sys/power/state
and the display comes back like it's supposed to.
Created attachment 70162 [details]
If this is still present in modern kernels please update the bug