| Message ID | 20220217144136.v3.2.I48b18ab197c9b649d376cf8cfd934e59d338f86d@changeid (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/2] drm/bridge: analogix_dp: Grab runtime PM reference for DP-AUX | expand |
Hi, On Thu, Feb 17, 2022 at 2:42 PM Brian Norris <briannorris@chromium.org> wrote: > > DP AUX transactions can consist of many short operations. There's no > need to power things up/down in short intervals. > > I pick an arbitrary 100ms; for the systems I'm testing (Rockchip > RK3399), runtime-PM transitions only take a few microseconds. > > Signed-off-by: Brian Norris <briannorris@chromium.org> > --- > > Changes in v3: > - New in v3 > > drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > index 16be279aed2c..d82a4ddf44e7 100644 > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > @@ -1121,7 +1121,7 @@ static int analogix_dp_get_modes(struct drm_connector *connector) > > pm_runtime_get_sync(dp->dev); > edid = drm_get_edid(connector, &dp->aux.ddc); > - pm_runtime_put(dp->dev); > + pm_runtime_put_autosuspend(dp->dev); So I think you can fully get rid of these ones now and rely on the ones in the aux transfer, right? > if (edid) { > drm_connector_update_edid_property(&dp->connector, > edid); > @@ -1642,7 +1642,7 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux, > > ret = analogix_dp_transfer(dp, msg); > out: > - pm_runtime_put(dp->dev); > + pm_runtime_put_autosuspend(dp->dev); > > return ret; > } > @@ -1775,6 +1775,8 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev) > if (ret) > return ret; > > + pm_runtime_use_autosuspend(dp->dev); > + pm_runtime_set_autosuspend_delay(dp->dev, 100); It's explicitly listed in the Documentation that you need the corresponding pm_runtime_dont_use_autosuspend(). Specifically, it says: > Drivers in ->remove() callback should undo the runtime PM changes done > in ->probe(). Usually this means calling pm_runtime_disable(), > pm_runtime_dont_use_autosuspend() etc. Not that it's very common to see anyone actually get it right, but I seem to remember running into an issue when I didn't do it. I think ti-sn65dsi86 still has it wrong since I found out about this later. Need to write a patch up for that... Basically you want to put it right before the two calls in your driver to pm_runtime_disable(). -Doug
On Tue, Feb 22, 2022 at 2:10 PM Doug Anderson <dianders@chromium.org> wrote: > On Thu, Feb 17, 2022 at 2:42 PM Brian Norris <briannorris@chromium.org> wrote: > > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > > @@ -1121,7 +1121,7 @@ static int analogix_dp_get_modes(struct drm_connector *connector) > > > > pm_runtime_get_sync(dp->dev); > > edid = drm_get_edid(connector, &dp->aux.ddc); > > - pm_runtime_put(dp->dev); > > + pm_runtime_put_autosuspend(dp->dev); > > So I think you can fully get rid of these ones now and rely on the > ones in the aux transfer, right? Yep, good catch. > > if (edid) { > > drm_connector_update_edid_property(&dp->connector, > > edid); > > @@ -1642,7 +1642,7 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux, > > > > ret = analogix_dp_transfer(dp, msg); > > out: > > - pm_runtime_put(dp->dev); > > + pm_runtime_put_autosuspend(dp->dev); > > > > return ret; > > } > > @@ -1775,6 +1775,8 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev) > > if (ret) > > return ret; > > > > + pm_runtime_use_autosuspend(dp->dev); > > + pm_runtime_set_autosuspend_delay(dp->dev, 100); > > It's explicitly listed in the Documentation that you need the > corresponding pm_runtime_dont_use_autosuspend(). Specifically, it > says: > > > Drivers in ->remove() callback should undo the runtime PM changes done > > in ->probe(). Usually this means calling pm_runtime_disable(), > > pm_runtime_dont_use_autosuspend() etc. > > Not that it's very common to see anyone actually get it right, but I > seem to remember running into an issue when I didn't do it. I think > ti-sn65dsi86 still has it wrong since I found out about this later. > Need to write a patch up for that... Basically you want to put it > right before the two calls in your driver to pm_runtime_disable(). Ack. Speaking of API misfeatures that we missed: I've failed to call pm_runtime_mark_last_busy(). I'll add that in the next rev, for the cases where we weren't already calling *_put_sync() (i.e., presumably we don't really care to wait around for autosuspend). *gripe* What a silly API. *gripe* Brian
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index 16be279aed2c..d82a4ddf44e7 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1121,7 +1121,7 @@ static int analogix_dp_get_modes(struct drm_connector *connector) pm_runtime_get_sync(dp->dev); edid = drm_get_edid(connector, &dp->aux.ddc); - pm_runtime_put(dp->dev); + pm_runtime_put_autosuspend(dp->dev); if (edid) { drm_connector_update_edid_property(&dp->connector, edid); @@ -1642,7 +1642,7 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux, ret = analogix_dp_transfer(dp, msg); out: - pm_runtime_put(dp->dev); + pm_runtime_put_autosuspend(dp->dev); return ret; } @@ -1775,6 +1775,8 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev) if (ret) return ret; + pm_runtime_use_autosuspend(dp->dev); + pm_runtime_set_autosuspend_delay(dp->dev, 100); pm_runtime_enable(dp->dev); ret = analogix_dp_create_bridge(drm_dev, dp);
DP AUX transactions can consist of many short operations. There's no need to power things up/down in short intervals. I pick an arbitrary 100ms; for the systems I'm testing (Rockchip RK3399), runtime-PM transitions only take a few microseconds. Signed-off-by: Brian Norris <briannorris@chromium.org> --- Changes in v3: - New in v3 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)