On Mon, Nov 12, 2018 at 04:12:10PM +0000, Wentland, Harry wrote: > On 2018-11-08 9:43 a.m., Nicholas Kazlauskas wrote: > > These include the drm_connector 'vrr_capable' and the drm_crtc > > 'vrr_enabled' properties. > > > > Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx> > > Cc: Harry Wentland <harry.wentland@xxxxxxx> > > Cc: Manasi Navare <manasi.d.navare@xxxxxxxxx> > > Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx> > > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > Cc: Michel Dänzer <michel@xxxxxxxxxxx> > > Looks good. Whole series is > Reviewed-by: Harry Wentland <harry.wentland@xxxxxxx> > > How are we with the userspace patches? We should probably hold off > pushing the kernel patches until the userspace work is all reviewed. Do some igts exist for this too? Especially for tricky pieces of uapi having a non-vendor reference code somewhere would be good, aside from testing and all that. -Daniel > > Harry > > > --- > > Documentation/gpu/drm-kms.rst | 7 ++++ > > drivers/gpu/drm/drm_connector.c | 68 +++++++++++++++++++++++++++++++++ > > 2 files changed, 75 insertions(+) > > > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > > index 4b1501b4835b..8da2a178cf85 100644 > > --- a/Documentation/gpu/drm-kms.rst > > +++ b/Documentation/gpu/drm-kms.rst > > @@ -575,6 +575,13 @@ Explicit Fencing Properties > > .. kernel-doc:: drivers/gpu/drm/drm_atomic_uapi.c > > :doc: explicit fencing properties > > > > + > > +Variable Refresh Properties > > +--------------------------- > > + > > +.. kernel-doc:: drivers/gpu/drm/drm_connector.c > > + :doc: Variable refresh properties > > + > > Existing KMS Properties > > ----------------------- > > > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > > index 49290060ab7b..0e4287461997 100644 > > --- a/drivers/gpu/drm/drm_connector.c > > +++ b/drivers/gpu/drm/drm_connector.c > > @@ -1255,6 +1255,74 @@ int drm_mode_create_scaling_mode_property(struct drm_device *dev) > > } > > EXPORT_SYMBOL(drm_mode_create_scaling_mode_property); > > > > +/** > > + * DOC: Variable refresh properties > > + * > > + * Variable refresh rate capable displays can dynamically adjust their > > + * refresh rate by extending the duration of their vertical front porch > > + * until page flip or timeout occurs. This can reduce or remove stuttering > > + * and latency in scenarios where the page flip does not align with the > > + * vblank interval. > > + * > > + * An example scenario would be an application flipping at a constant rate > > + * of 48Hz on a 60Hz display. The page flip will frequently miss the vblank > > + * interval and the same contents will be displayed twice. This can be > > + * observed as stuttering for content with motion. > > + * > > + * If variable refresh rate was active on a display that supported a > > + * variable refresh range from 35Hz to 60Hz no stuttering would be observable > > + * for the example scenario. The minimum supported variable refresh rate of > > + * 35Hz is below the page flip frequency and the vertical front porch can > > + * be extended until the page flip occurs. The vblank interval will be > > + * directly aligned to the page flip rate. > > + * > > + * Not all userspace content is suitable for use with variable refresh rate. > > + * Large and frequent changes in vertical front porch duration may worsen > > + * perceived stuttering for input sensitive applications. > > + * > > + * Panel brightness will also vary with vertical front porch duration. Some > > + * panels may have noticeable differences in brightness between the minimum > > + * vertical front porch duration and the maximum vertical front porch duration. > > + * Large and frequent changes in vertical front porch duration may produce > > + * observable flickering for such panels. > > + * > > + * Userspace control for variable refresh rate is supported via properties > > + * on the &drm_connector and &drm_crtc objects. > > + * > > + * "vrr_capable": > > + * Optional &drm_connector boolean property that drivers should attach > > + * with drm_connector_attach_vrr_capable_property() on connectors that > > + * could support variable refresh rates. Drivers should update the > > + * property value by calling drm_connector_set_vrr_capable_property(). > > + * > > + * Absence of the property should indicate absence of support. > > + * > > + * "vrr_enabled": > > + * Default &drm_crtc boolean property that notifies the driver that the > > + * content on the CRTC is suitable for variable refresh rate presentation. > > + * The driver will take this property as a hint to enable variable > > + * refresh rate support if the receiver supports it, ie. if the > > + * "vrr_capable" property is true on the &drm_connector object. The > > + * vertical front porch duration will be extended until page-flip or > > + * timeout when enabled. > > + * > > + * The minimum vertical front porch duration is defined as the vertical > > + * front porch duration for the current mode. > > + * > > + * The maximum vertical front porch duration is greater than or equal to > > + * the minimum vertical front porch duration. The duration is derived > > + * from the minimum supported variable refresh rate for the connector. > > + * > > + * The driver may place further restrictions within these minimum > > + * and maximum bounds. > > + * > > + * The semantics for the vertical blank timestamp differ when > > + * variable refresh rate is active. The vertical blank timestamp > > + * is defined to be an estimate using the current mode's fixed > > + * refresh rate timings. The semantics for the page-flip event > > + * timestamp remain the same. > > + */ > > + > > /** > > * drm_connector_attach_vrr_capable_property - creates the > > * vrr_capable property > > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
