From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Date: Mon, 22 Dec 2014 15:53:03 +0000 Subject: Re: [PATCH v2 4/7] imx-drm: ipuv3-crtc: Implement mode_fixup Message-Id: <20141222155303.GB32333@pengutronix.de> List-Id: References: <1418954426-21909-1-git-send-email-steve_longerbeam@mentor.com> <1418954426-21909-5-git-send-email-steve_longerbeam@mentor.com> <20141220155254.GJ11285@n2100.arm.linux.org.uk> In-Reply-To: <20141220155254.GJ11285@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Russell King - ARM Linux Cc: Steve Longerbeam , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org, David Airlie , Philipp Zabel , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Fabio Estevam , Shawn Guo , Denis Carikli , Jiada Wang , Steve Longerbeam Hi Russell, On Sat, Dec 20, 2014 at 03:52:54PM +0000, Russell King - ARM Linux wrote: > On Thu, Dec 18, 2014 at 06:00:23PM -0800, Steve Longerbeam wrote: > > Ask the IPU display interface, via ipu_di_adjust_videomode(), to > > adjust a video mode to meet any DI restrictions. The function takes > > a subsystem independent videomode, so the drm_display_mode must be > > converted to videomode first, and then the adjusted mode converted > > back to a drm_display_mode. > > What is the reason to use videomode (apart from it being subsystem > independent)? Do we forsee implementation of other output subsystems > for the IPU? There might be the issue of possible CSI -> IC -> DC -> DI passthrough, where the DI timing must be synchronized to the CSI input signal. I haven't really thought about how that should be integrated with the DRM driver mostly because of the 1024 pixel output width maximum in the IC, which limits the usefulness somewhat. I like the use of struct videomode here for the symmetry with patch 6. But currently, we could make ipu_di_adjust_videomode take a drm_display_mode just as well. regards Philipp