On Tue, Nov 22, 2016 at 11:37 PM, Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: > Hi, > > On Fri, Nov 18, 2016 at 10:22:40AM +0800, Chen-Yu Tsai wrote: >> On Fri, Nov 18, 2016 at 3:02 AM, Maxime Ripard >> <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: >> > On Wed, Nov 16, 2016 at 05:37:31PM +0800, Chen-Yu Tsai wrote: >> >> The sun4i DRM driver counts the number of endpoints it found and >> >> registers the whole DRM pipeline if any endpoints are found. >> >> >> >> However, if the TCON and its child endpoints (LCD panels, TV encoder, >> >> HDMI encoder, MIPI DSI encoder, etc.) aren't found, that means we >> >> don't have any usable CRTCs, and the display pipeline is incomplete >> >> and useless. >> > >> > If some node set as available is not probed, then yes, it does, but >> > I'm not really sure how it's a problem. Quite the opposite actually. >> >> Actually the problem occurs when the TCON is _not_ available, but >> the other endpoints preceding it are. > > By preceding, you mean the display engine or the HDMI or TV encoders? The display engine. >> >> The debug message "Queued %d outputs on pipeline %d\n" is also telling. >> >> >> >> This patch makes the driver only count enabled TCON endpoints. If >> >> none are found, the DRM pipeline is not used. This avoids screwing >> >> up the simple framebuffer provided by the bootloader in cases where >> >> we aren't able to support the display with the DRM subsystem, due >> >> to lack of panel or bridge drivers, or just lack of progress. >> > >> > The framebuffer is removed only at bind time, which means that all the >> > drivers have probed already. Lack of progress isn't an issue here, >> > since the node simply won't be there, and we wouldn't have it in the >> > component lists. And lack of drivers shouldn't be an issue either, >> > since in order for bind to be called, all the drivers would have >> > gone through their probe. >> > >> > So I'm not really sure what it fixes. >> >> To recap, on sun6i I had enabled the display engine node by default >> in the dtsi, along with the backend and drc. The tcon is disabled >> by default, so it doesn't get added to the list of components. >> The available components get probed, binded, and simplefb gets >> pushed out. >> >> I suppose disabling the display engine by default would be better? >> At least simplefb still works. > > Yep, that works for me. OK. I'll send out a patch. ChenYu _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
