On Wed, Aug 26, 2015 at 01:38:36PM -0400, Rob Clark wrote:
On Wed, Aug 26, 2015 at 12:30 PM, Ville Syrjälä ville.syrjala@linux.intel.com wrote:
On Wed, Aug 26, 2015 at 12:07:30PM -0400, Rob Clark wrote:
On Wed, Aug 26, 2015 at 12:03 PM, Rob Clark robdclark@gmail.com wrote:
On Wed, Aug 26, 2015 at 11:41 AM, Daniel Vetter daniel.vetter@ffwll.ch wrote:
Very strictly speaking this is possible if you have special hw and genlocked CRTCs. In general switching a plane between two active CRTC just won't work so well and is probably not tested at all. Just forbid it.
So, I expect msm should actually be able to do this w/ dual-dsi (where we are using two CRTC's, w/ synchronized flushes)..
Probably someone who has a dual-dsi panel should actually test that to confirm. But it seems like it should work. Maybe we need something in 'struct drm_crtc' so core can realize that two CRTC's are locked together..
oh, and for most drivers, switching plane between CRTCs without an off-cycle would probably also work for DSI cmd mode..
You'd need to wait for any ongoing transfer on the old crtc to finish before moving the plane. So that's not really any different than the driver doing the dance with a vblank wait on a video mode display.
except that update would need to block from previous xfer anyways, so there isn't really a race w/ frame n+1 like there would be with video mode..
Why would it block if it's on a separate crtc?