[Intel-gfx] Design review request: DRM color manager

David Herrmann dh.herrmann at gmail.com
Mon May 12 09:00:23 PDT 2014


On Mon, May 12, 2014 at 5:28 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
> Those are all just reasons for atomic modeset and maybe an atomic modeget
> ioctl which transfers the entire blob of things. Maybe we should start
> with the atomic modeget to get things rolling. Otoh you can always do that
> in userspace since we assume there's only one display manager.

DRM_MODE_OBJ_GET_PROPERTIES is already available and allows atomic
retrieval of 'n' properties (as it calls drm_modeset_lock_all()). I
guess that qualifies as what you describe with "atomic modeget"?

> And for modeset we can throw efficiency of the marshalling/de-marshalling
> over board (within some limits of course) since we do about 60*num_pipes
> modeset/pageflip calls per second at most. And the overhead of the
> encoding/decoding of the properties will be completely washed out by all
> the register i/o we need to do to UC pci bars.

Yepp, I fully agree. And if properties turn out to become a
bottleneck, we should optimize them.


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