Hi Thierry, Am Dienstag, 10. November 2015, 18:32:57 schrieb Thierry Reding: > On Tue, Nov 10, 2015 at 03:18:10PM +0100, Heiko Stuebner wrote: > > Hi Philipp, > > > > Am Montag, 2. November 2015, 17:55:56 schrieb Philipp Zabel: > > > If the driver is probed from the device tree, and there is a phandle > > > property set on it, and the enable GPIO is already configured as output, > > > and the backlight is currently disabled, keep it disabled. > > > If all these conditions are met, assume there will be some other driver > > > that can enable the backlight at the appropriate time. > > > > > > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > > > Reviewed-by: Christian Gmeiner <christian.gmeiner@xxxxxxxxx> > > > > this patch improves the white screen when booting a veyron chromebook > > a lot. I still see a small white flash, but that can probably come from > > the WIP edp driver. > > Some panels require a couple of frames before they actually enable. You > may want to look at the datasheet of your panel to see if it has some > specific requirement and update the panel driver with that. > > From a high-level view the way that this is supposed to work is that > your encoder driver (e.g. eDP) "prepares" the panel, then starts sending > frames and finally "enables" the panel. With something like the simple > panel driver you can influence this by setting the delay.enable field in > the panel descriptor. > > See struct panel_desc in drivers/gpu/drm/panel/panel-simple.c Thanks for the pointers :-) Just to follow up a little bit, after moving to Yakir's Analogix-dp driver from the chromeos-one I was using till now, that actually works nicely for me and even the short flash is gone. Heiko
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