Messages in this thread Patch in this message | | | Date | Mon, 24 May 2021 23:22:18 +0300 | From | Laurent Pinchart <> | Subject | Re: [PATCH v7 01/10] drm/panel: panel-simple: Add missing pm_runtime_dont_use_autosuspend() calls |
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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);
-- Regards,
Laurent Pinchart
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