Messages in this thread | | | Date | Fri, 20 Apr 2018 07:25:33 -0700 | From | Tony Lindgren <> | Subject | Re: [PATCHv3 3/8] drm/omap: add support for manually updated displays |
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Hi,
* Daniel Stone <daniel@fooishbar.org> [180420 10:21]: > Hi Tomi, > > On 20 April 2018 at 08:09, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote: > > It's actually not quite clear to me how manual update displays work with > > DRM... > > > > As far as I see, we have essentially two cases: 1) single buffering, > > where the userspace must set an area in the fb dirty, which then > > triggers the update, 2) multi buffering, which doesn't need fb dirty, > > but just a page flip which triggers the update. > > > > In the 2) case (which I think is the optimal case which all the modern > > apps should use), there's no need for delayed work or any work, and the > > code flow should be very similar to the auto-update model. > > Correct. There's been talk (and I think patches?) of adding a > per-plane dirty property, so userspace can as an optimisation inform > the kernel of the area changed between frames. But short of that, a > pageflip needs to trigger a full-plane update, with no dirtyfb > required.
For per-plane dirty property patches, which ones do you refer to?
Then for xorg, there's my second attempt on fixing the command mode rotation at [0]. Not sure if that's enough for a fix?
It seems not very efficient to me and I don't really know where the the per crtc dirty flag should be stored..
I can easily test patches though with a command mode LCD and normal HDMI setup on droid 4.
Regards,
Tony
[0] https://lists.x.org/archives/xorg-devel/2018-February/055890.html
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