On Thu, Aug 14, 2014 at 08:33:23PM +0200, Daniel Vetter wrote: > On Thu, Aug 14, 2014 at 7:58 PM, Ville Syrjälä > <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > Sure but the user can supply any mode, doesn't have to be on any list. > > And the only sane rule for the frobbing would be that you can (slightly) > > reduce hdisp/vdisp but never expand them so that there will never be any > > extra garbage exposed (and the FB might not be big enough anyway). But > > even reducing hdisp/vdisp by one pixel can be enough to anger the > > hardware if a plane then extends one pixel into the blanking. > > > > This isn't much of a problem for i915 though. The hardware is generally > > good enough to not need it. Double wide and (s)dvo/lvds gang mode are > > the only exception that comes to mind. Even there we just need to make > > pipe src width even, but still that's something we have to account > > when clipping planes. > > > > On older hardware there were generally more restrictions eg. some > > legacy baggage from VGA days which required horizontal timings to > > be multiples of 8. I also "fondly" remember much more magic timing > > restrictions in certain pieces hardware which were something close > > to "if (foo*bar % this == that) frob else don't". IMO these kinds of > > restrictions are too magic to make rejecting the mode an option, > > so frobbing is the lesser of two evils. > > Imo the mode list we provide should be reasonable for everyone, and if > you start to add your own modes then I expect the user to do that > adjusting for us. Nowadays there should be very few cases where we > don't provide decent mode lists and where it's not a super-special > embedded thing where you need to configure everything yourself anyway. > So I don't think we should ever adjust the input region for a crtc. That's fine for decent hardware. But if/when I write a driver for old junk I'm probably going to frob no matter what anyone says :) -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
