Deprecation of AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED

[Michel Dänzer]

On 30/06/17 12:03 AM, Marek Olšák wrote:
> Do you have any concern if we also stop using the CPU_ACCESS flag on radeon?

No concern from my side for radeon.


> On Thu, Jun 29, 2017 at 4:51 PM, Christian König
> <deathsimple at vodafone.de> wrote:
>> Yeah, I was thinking something similar.
>>
>> See the intention behind CPU_ACCESS_REQUIRED is to always guarantee that CPU
>> access is immediately possible.
>>
>> If you ask me that is not really useful for the UMD and was never meant to
>> be used by Mesa (only the closed source UMD and some kernel internal use
>> cases).
>>
>> I would like to keep the behavior in the kernel driver as it is, but we
>> should really stop using this as a hint in Mesa.

So we'd have a flag in the userspace ABI which is only used by closed
source userspace, and which can be used to artificially create pressure
on CPU visible VRAM. I know somebody who would argue vehemently against
adding something like that. :)

What does the closed source UMD use the flag for?


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