On Tue, Dec 03, 2019 at 09:39:36AM +0100, Sam Ravnborg wrote: > On Tue, Dec 03, 2019 at 08:46:59AM +0100, Maxime Ripard wrote: > > Hi, > > > > On Mon, Dec 02, 2019 at 08:32:11PM +0100, Sam Ravnborg wrote: > > > There was no users - so remove it. > > > The callback was implemented in two drivers - deleted. > > > > > > Signed-off-by: Sam Ravnborg > > > Cc: Thierry Reding > > > Cc: Laurent Pinchart > > > Cc: Sam Ravnborg > > > Cc: Maarten Lankhorst > > > Cc: Maxime Ripard > > > Cc: David Airlie > > > Cc: Daniel Vetter > > > --- > > > drivers/gpu/drm/panel/panel-seiko-43wvf1g.c | 18 ------------------ > > > drivers/gpu/drm/panel/panel-simple.c | 18 ------------------ > > > include/drm/drm_panel.h | 9 --------- > > > 3 files changed, 45 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c b/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c > > > index b878930b17e4..3bcba64235c4 100644 > > > --- a/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c > > > +++ b/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c > > > @@ -217,30 +217,12 @@ static int seiko_panel_get_modes(struct drm_panel *panel, > > > return seiko_panel_get_fixed_modes(p, connector); > > > } > > > > > > -static int seiko_panel_get_timings(struct drm_panel *panel, > > > - unsigned int num_timings, > > > - struct display_timing *timings) > > > -{ > > > - struct seiko_panel *p = to_seiko_panel(panel); > > > - unsigned int i; > > > - > > > - if (p->desc->num_timings < num_timings) > > > - num_timings = p->desc->num_timings; > > > - > > > - if (timings) > > > - for (i = 0; i < num_timings; i++) > > > - timings[i] = p->desc->timings[i]; > > > - > > > - return p->desc->num_timings; > > > -} > > > - > > > static const struct drm_panel_funcs seiko_panel_funcs = { > > > .disable = seiko_panel_disable, > > > .unprepare = seiko_panel_unprepare, > > > .prepare = seiko_panel_prepare, > > > .enable = seiko_panel_enable, > > > .get_modes = seiko_panel_get_modes, > > > - .get_timings = seiko_panel_get_timings, > > > }; > > > > If anything, I think we should grow the usage of timings and / or make > > it usable by everyone. > > > > Using only the mode as we do currently has a bunch of shortcomings as > > almost no encoder will be able to provide the typical pixel clock, and > > that situation leads to multiple things: > > > > - If someone working on one encoder wants to upstream a panel they > > have tested, chances are this will not be the typical pixel clock > > / timings being used but rather the one that will match what that > > SoC is capable of. Trouble comes when a second user comes in with > > a different encoder and different capabilities, and then we have a > > maintainance fight over which timing is the true timing (with a > > significant chance that none of them are). > > > > - If we can't match the pixel clock, we currently have no easy way > > to make the usual measures of reducing / growing the porches and > > blankings areas to match the pixel clock we can provide, since we > > don't have an easy way to get the tolerance on those timings for a > > given panel. There's some ad hoc solutions on some drivers (I > > think vc4 has that?) to ignore the panel and just play around with > > the timings, but I think this should be generalised. > > > > Timings solves the first case since we have the operating range now > > and not a single set of timings, and it solves the second since we can > > use that range to take those measures instead of taking a shot in the > > dark. > > > > I appreciate that it's pretty far from where we are today, but > > removing the get_timings means that all the timings already defined in > > the panel drivers are becoming useless too, and that eventually it > > will get removed. > > Thanks for this nice explanation. I will drop the patch, > and add an entry to my TODO list to look closer at this later. > There are things to improve in this area. > > So the conclusion is more work rather than removing code :-) Yeah, unfortunately.. :) Maxime