[PATCH] drm/radeon: Only flush HDP cache from idle ioctl if BO is in VRAM

Michel Dänzer michel at daenzer.net
Tue Aug 5 01:55:34 PDT 2014

On 05.08.2014 07:01, Marek Olšák wrote:
> I'm afraid this won't always work and it can be a source of bugs.
> Userspace doesn't have to call GEM_WAIT_IDLE before a CPU access to a
> VRAM buffer. For example, consider a wait-idle request with a non-zero
> timeout, which is implemented as a loop which calls GEM_BUSY. Also,
> userspace can use fences (alright they are backed by 1-page-sized VRAM
> buffers at the moment) and it may use real fences in the future which
> are not tied to a buffer object.
> If the HDP flush isn't allowed in userspace IBs, I think we will have
> to expose it as an ioctl and call it explicitly from userspace.

I understand your concerns, but my patch doesn't change anything wrt
them, does it?

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

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