On Wed, May 02, 2018 at 04:57:09PM +0100, Chris Wilson wrote: > Quoting Ville Syrjälä (2018-05-02 16:52:41) > > On Wed, May 02, 2018 at 04:33:30PM +0100, Chris Wilson wrote: > > > Quoting Ville Syrjala (2018-04-26 17:30:15) > > > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > > > > > During state readout we first read out the pipe src size, store > > > > that information in the user mode h/vdisplay, but later on we overwrite > > > > that with the actual crtc timings. That makes our read out crtc state > > > > inconsistent with itself when the BIOS has enabled the panel fitter to > > > > scale the pipe contents. Let's preserve the pipe src size based > > > > information in the user mode to make things consistent again. > > > > > > The question I don't feel answered is: If this is the BIOS mode, why > > > aren't we filling it from get_hw_state? > > > > I suppose the answer is that we're only filling out the bare minimum > > of information during the basic readout. That is everything we need > > for intel_pipe_config_compare() to do its job. Later on we fill the > > gaps to make the state actually presentable to userspace. We don't > > have to do that if the state we read out isn't actually going to be > > exposed to userspace. > > > > I suppose we could consider doing a more thorough job up front, but > > I think we'd need to spend some though on eg. the handling of the > > mode blob. We probably wouldn't want userspace to gain access to > > our short lived internal mode blob created from the read out state. > > Will we run into a problem where we say the current mode is 800x600, but > is in fact 1024x768 scaledfrom 800x600? E.g. if we for whatever reason > want to switch to a real 800x600 mode? Seems unlikely that the real 800x600 mode would have the same blanking lengths and clock as the 1024x768 mode. So we should end up with a full modeset. I was actually wondering whether we should make the scaled 800x600 mode look more like a proper 800x600 mode, ie. that the blanking lengths and clock would also get scaled proportionally to the h/vdisplay. That would more closely match the "fullscreen" scaling mode, whereas the way we do it here would match the "center" scaling mode. But I guess we generally just have to ingore the blanking lengths when scaling is involved, so migth as well leave the original timings in place apart from hdisplay/vdisplay. It's somewhat unfortunate that we don't have a better uapi than "fake the timings" for pipe scaling :( -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
