Hi Doug,
Thank you for the patch.
On Mon, May 17, 2021 at 01:08:58PM -0700, Douglas Anderson wrote:
The PM Runtime docs specifically call out the need to call pm_runtime_dont_use_autosuspend() in the remove() callback if pm_runtime_use_autosuspend() was called in probe():
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.
~/src/kernel/linux $ git grep pm_runtime_use_autosuspend -- drivers | wc -l 209 ~/src/kernel/linux $ git grep pm_runtime_dont_use_autosuspend -- drivers | wc -l 80
Seems like a lost battle :-(
The fix is right, but I wonder if this shouldn't be handled automatically by the runtime PM core. The runtime PM API is notoriously difficult to use correctly.
We should do this. This fixes a warning splat that I saw when I was testing out the panel-simple's remove().
Fixes: 3235b0f20a0a ("drm/panel: panel-simple: Use runtime pm to avoid excessive unprepare / prepare") Signed-off-by: Douglas Anderson dianders@chromium.org
Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
Changes in v7:
- pm_runtime_dont_use_autosuspend() fix new for v7.
drivers/gpu/drm/panel/panel-simple.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c index 9be050ab372f..21939d4352cf 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -798,6 +798,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc) return 0;
disable_pm_runtime:
- pm_runtime_dont_use_autosuspend(dev); pm_runtime_disable(dev);
free_ddc: if (panel->ddc) @@ -814,6 +815,7 @@ static int panel_simple_remove(struct device *dev) drm_panel_disable(&panel->base); drm_panel_unprepare(&panel->base);
- pm_runtime_dont_use_autosuspend(dev); pm_runtime_disable(dev); if (panel->ddc) put_device(&panel->ddc->dev);