| Message ID | 1441713165-24465-1-git-send-email-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Daniel, Thank you for the patch. On Tuesday 08 September 2015 13:52:45 Daniel Vetter wrote: > Requested by Laurent. > > Note that this uses the new markdown support which will only land in > kernel 4.4 (for the code snippet). > > v2: A few spelling fixes I spotted myself. > > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Reviewed-by: Thierry Reding <treding@nvidia.com> (v1 on irc) > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> > --- > drivers/gpu/drm/drm_atomic_helper.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c > b/drivers/gpu/drm/drm_atomic_helper.c index 12c25c54309f..bd23b4dc7f43 > 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -993,6 +993,22 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_vblanks); > * object. This can still fail when e.g. the framebuffer reservation fails. > * For now this doesn't implement asynchronous commits. > * > + * Note that right now this function does not support async commits, and > + * hence driver writers must implement their own version for now. Also note > + * that the default ordering of how the various stages are called is to > + * match the legacy modeset helper library closest. One peculiarity of that > + * is that it doesn't mesh well with runtime pm at all. > + * > + * For drivers supporting runtime PM the recommended sequence is > + * > + * drm_atomic_helper_commit_modeset_disables(dev, state); > + * > + * drm_atomic_helper_commit_modeset_enables(dev, state); > + * > + * drm_atomic_helper_commit_planes(dev, state, true); > + * > + * See the kerneldoc entries for these three functions for more details. > + * > * RETURNS > * Zero for success or -errno. > */ > @@ -1168,6 +1184,12 @@ bool plane_crtc_active(struct drm_plane_state *state) > * Note that this function does all plane updates across all CRTCs in one > * step. If the hardware can't support this approach look at > * drm_atomic_helper_commit_planes_on_crtc() instead. > + * > + * Note that for drivers supporting runtime PM, or which are otherwise > + * unhappy if their plane update hooks get called on CRTCs which are off, > + * it is highly recommended to set @active_only to true. Setting > + * @active_only to false as the default implementation in > + * drm_atomic_helper_commit() does is just done to most closely match > + * the behaviour of the legacy helpers. How about "Plane parameters can be updated by applications while the associated CRTC is disabled. The DRM/KMS core will store the parameters in the plane state, which will be available to the driver when the CRTC is turned on. As a result most drivers don't need to be immediately notified of plane updates for a disabled CRTC. Unless otherwise needed, drivers are advised to set the @active_only parameters to true in order not to receive plane update notifications related to a disabled CRTC." > */ > void drm_atomic_helper_commit_planes(struct drm_device *dev, > struct drm_atomic_state *old_state,
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 12c25c54309f..bd23b4dc7f43 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -993,6 +993,22 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_vblanks); * object. This can still fail when e.g. the framebuffer reservation fails. For * now this doesn't implement asynchronous commits. * + * Note that right now this function does not support async commits, and hence + * driver writers must implement their own version for now. Also note that the + * default ordering of how the various stages are called is to match the legacy + * modeset helper library closest. One peculiarity of that is that it doesn't + * mesh well with runtime pm at all. + * + * For drivers supporting runtime PM the recommended sequence is + * + * drm_atomic_helper_commit_modeset_disables(dev, state); + * + * drm_atomic_helper_commit_modeset_enables(dev, state); + * + * drm_atomic_helper_commit_planes(dev, state, true); + * + * See the kerneldoc entries for these three functions for more details. + * * RETURNS * Zero for success or -errno. */ @@ -1168,6 +1184,12 @@ bool plane_crtc_active(struct drm_plane_state *state) * Note that this function does all plane updates across all CRTCs in one step. * If the hardware can't support this approach look at * drm_atomic_helper_commit_planes_on_crtc() instead. + * + * Note that for drivers supporting runtime PM, or which are otherwise unhappy if + * their plane update hooks get called on CRTCs which are off, it is highly + * recommended to set @active_only to true. Setting @active_only to false as the + * default implementation in drm_atomic_helper_commit() does is just done to + * most closely match the behaviour of the legacy helpers. */ void drm_atomic_helper_commit_planes(struct drm_device *dev, struct drm_atomic_state *old_state,