Re: [PATCH] drm/radeon: Fix regression with suspend/resume

[Ross Zwisler <ross.zwisler@linux.intel.com>]

On Wed, 2015-02-18 at 13:02 +0100, Christian König wrote:
> Well, what the patch does is just changing where buffers are placed in 
> memory. E.g. now we place the buffer at the end of memory as well.
> 
> So I can imagine at least three possible causes for the issues you see:
> 1. We haven't implemented all buffer placement restrictions correctly 
> and without the patch everything just works fine by coincident.
> 2. Something is overwriting the buffer at it's new location. 
> @Alex&Michel: Didn't we had a similar problem internally recently? Or 
> was that just for APUs?
> 3. One of the memory chips on your hardware is faulty and without the 
> patch the we just don't use the affected region (rather unlikely).
> 
> For testing could you try to limit the amount of VRAM used? E.g. give 
> radeon.vramlimit=256 as kernel commandline to limit the VRAM to the 
> first 256MB.

Tried with the kernel parameter radeon.vramlimit=256, and it seemed to have
the exact same behavior.  The flicker was still there, same size, same
frequency.

Thanks,
- Ross