On Thu, 2 Jun 2016 23:57:02 +0200 Daniel Vetter <daniel@xxxxxxxx> wrote: > On Thu, Jun 2, 2016 at 11:05 PM, Laurent Pinchart > <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > > Hi Boris, > > > > Thank you for the patch. > > > > On Thursday 02 Jun 2016 16:31:28 Boris Brezillon wrote: > >> Adapt drm_pick_crtcs() and update_connector_routing() to fallback to > >> drm_atomic_helper_best_encoder() if funcs->best_encoder() is NULL so > >> that DRM drivers can leave this hook unassigned if they know they want > >> to use drm_atomic_helper_best_encoder(). > > > > Could you please update include/drm/drm_modeset_helper_vtables.h to document > > this new behaviour ? > > Thanks for reminding me. Please update hooks for both > atomic_best_encoder and best_encoder. Also mention that it's only > optional for atomic drivers. There's lots of examples in that file for > the wording usually used. Hm, I haven't changed anything for the ->atomic_best_encoder() hook, or am I missing something? > > > The only drawback I see in this patch is the additional object lookup > > performed by drm_atomic_helper_best_encoder() at runtime. I wonder if we could > > somehow cache the information, as the assignment can't change when there's a > > 1:1 correspondence between encoders and connectors. > > drm_encoder_find is an idr lookup. That should be plenty fast, > especially for modeset code. Usually what's too expensive even for > modeset code is linear list walks. But Chris just submitted patches to > convert most of them into simple lookups. > -Daniel > > >>> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> > >> --- > >> drivers/gpu/drm/drm_atomic_helper.c | 4 +++- > >> drivers/gpu/drm/drm_fb_helper.c | 13 ++++++++++++- > >> 2 files changed, 15 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/drm_atomic_helper.c > >> b/drivers/gpu/drm/drm_atomic_helper.c index f6a3350..849d029 100644 > >> --- a/drivers/gpu/drm/drm_atomic_helper.c > >> +++ b/drivers/gpu/drm/drm_atomic_helper.c > >> @@ -300,8 +300,10 @@ update_connector_routing(struct drm_atomic_state > >> *state, if (funcs->atomic_best_encoder) > >> new_encoder = funcs->atomic_best_encoder(connector, > >> connector_state); > >> - else > >> + else if (funcs->best_encoder) > >> new_encoder = funcs->best_encoder(connector); > >> + else > >> + new_encoder = drm_atomic_helper_best_encoder(connector); > >> > >> if (!new_encoder) { > >> DRM_DEBUG_ATOMIC("No suitable encoder found for [CONNECTOR:%d:%s]\n", > >> diff --git a/drivers/gpu/drm/drm_fb_helper.c > >> b/drivers/gpu/drm/drm_fb_helper.c index 7c2eb75..d44389a 100644 > >> --- a/drivers/gpu/drm/drm_fb_helper.c > >> +++ b/drivers/gpu/drm/drm_fb_helper.c > >> @@ -2000,7 +2000,18 @@ static int drm_pick_crtcs(struct drm_fb_helper > >> *fb_helper, my_score++; > >> > >> connector_funcs = connector->helper_private; > >> - encoder = connector_funcs->best_encoder(connector); > >> + > >> + /* > >> + * If the DRM device implements atomic hooks and ->best_encoder() is > >> + * NULL we fallback to the default drm_atomic_helper_best_encoder() > >> + * helper. > >> + */ > >> + if (fb_helper->dev->mode_config.funcs->atomic_commit && > >> + !connector_funcs->best_encoder) > >> + encoder = drm_atomic_helper_best_encoder(connector); > >> + else > >> + encoder = connector_funcs->best_encoder(connector); > >> + > >> if (!encoder) > >> goto out; > > > > -- > > Regards, > > > > Laurent Pinchart > > > > > -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com