From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCHv3 3/8] drm/omap: add support for manually updated displays Date: Fri, 20 Apr 2018 07:44:01 -0700 Message-ID: <20180420144401.GO5671@atomide.com> References: <20180330171822.25896-1-sebastian.reichel@collabora.co.uk> <20180330171822.25896-4-sebastian.reichel@collabora.co.uk> <20180420142533.GN5671@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Daniel Stone Cc: Tomi Valkeinen , Sebastian Reichel , Sebastian Reichel , Pavel Machek , Laurent Pinchart , Rob Herring , Mark Rutland , dri-devel , devicetree@vger.kernel.org, linux-omap@vger.kernel.org, Linux Kernel Mailing List , kernel@collabora.com List-Id: devicetree@vger.kernel.org * Daniel Stone [180420 14:41]: > Hi Tony! > > On 20 April 2018 at 15:25, Tony Lindgren wrote: > > * Daniel Stone [180420 10:21]: > >> On 20 April 2018 at 08:09, Tomi Valkeinen 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? > > Here's the latest iteration of that series: > https://lists.freedesktop.org/archives/dri-devel/2018-April/171900.html > <1522885748-67122-1-git-send-email-drawat@vmware.com> OK thanks for the link. > > 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 try to deny all knowledge of X11 these days, I'm afraid. :) Tony