On Tue, May 12, 2015 at 08:35:58AM +0200, Daniel Vetter wrote: > On Mon, May 11, 2015 at 04:34:57PM +0000, Mark Zhang wrote: > > I just want to make things easier. If we adding this in panel's meta > > data, it will be harder to make crtc gets this, since normally encoder > > talks with panel and crtc talks with encoder. But yes, adding this in > > panel's metadata makes more sense so if there is a better way to do > > that, I'm happy to do the changes. > > Adding something to the userspace ABI (which you've done here) because the > kernel-internals are designed in an awkward way right now is definitely > the wrong thing to do. With atomic you can easily add a bool > prefer_oneshot to drm_crtc_state to encode this. But I fear that with the > plain crtc helpers this just doesn't work properly. You could add a > driver-private internal in drm_display_mode->private_flags, but that might > clash with drivers existing use of this field. > > In any way, this is definitely not something to add to uapi headers. Hence > Nacked-by: me. Are there use-cases where one-shot mode is worse than continuous mode? I'm thinking games that run at full FPS and such. If so, exposing this to userspace is perhaps not a bad idea, albeit not via a mode flag. If userspace had a way to set the preference, it could do so depending on use-case. Thierry > > ________________________________________ > > From: Daniel Vetter <daniel.vetter@xxxxxxxx> on behalf of Daniel Vetter <daniel@xxxxxxxx> > > Sent: Monday, May 11, 2015 5:27 PM > > To: Mark Zhang > > Cc: thierry.reding@xxxxxxxxx; linux-tegra@xxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx > > Subject: Re: [RFC PATCH 01/12] drm: Add a new mode flag: DRM_MODE_FLAG_PREFER_ONE_SHOT > > > > On Mon, May 11, 2015 at 09:38:20AM +0800, Mark Zhang wrote: > > > Normally this flag is set by panel driver so that crtc can enable > > > the "one-shot" mode(not scan frames continuously). > > > > > > Signed-off-by: Mark Zhang <markz@xxxxxxxxxx> > > > --- > > > include/uapi/drm/drm_mode.h | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h > > > index dbeba949462a..5447a338e893 100644 > > > --- a/include/uapi/drm/drm_mode.h > > > +++ b/include/uapi/drm/drm_mode.h > > > @@ -72,6 +72,7 @@ > > > #define DRM_MODE_FLAG_3D_L_DEPTH_GFX_GFX_DEPTH (6<<14) > > > #define DRM_MODE_FLAG_3D_TOP_AND_BOTTOM (7<<14) > > > #define DRM_MODE_FLAG_3D_SIDE_BY_SIDE_HALF (8<<14) > > > +#define DRM_MODE_FLAG_PREFER_ONE_SHOT (1<<19) > > > > tbh this doesn't sound like a mode flag, but something which should be > > attached to the drm_panel. Especially since all the single-frame modes are > > highly sink/link specific. Why was this added here instead of to the > > drm_panel metadata? > > -Daniel > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch > > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch
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