[mipsel+rs780e]Occasionally "GPU lockup" after resuming from suspend.

[Michel Dänzer]

On Don, 2011-12-08 at 19:35 +0800, chenhc at lemote.com wrote:
> 
> I found CP_RB_WPTR has changed when "ring test failed", so I think CP is
> active, but what it get from ring buffer is wrong.

CP_RB_WPTR is normally only changed by the CPU after adding commands to
the ring buffer, so I'm afraid that may not be a valid conclusion. 


> Then, I want to know whether there is a way to check the content that
> GPU get from ring buffer. 

See the r100_debugfs_cp_csq_fifo() function, which generates the output
for /sys/kernel/debug/dri/0/r100_cp_csq_fifo. 


> BTW, when I use "echo shutdown > /sys/power/disk; echo disk >
> /sys/power/state" to do a hibernation, there will be occasionally "GPU
> reset" just like suspend. However, if I use "echo reboot >
> /sys/power/disk; echo disk > /sys/power/state" to do a hibernation and
> wakeup automatically, there is no "GPU reset" after hundreds of tests.
> What does this imply? Power loss cause something break?

Yeah, it sounds like the resume code doesn't properly re-initialize
something that's preserved on a warm boot but lost on a cold boot. 


-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer