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