| Message ID | 20231123175425.496956-2-u.kleine-koenig@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bridge: ti-sn65dsi86: Some updates | expand |
On 23/11/2023 18:54, Uwe Kleine-König wrote: > pm_runtime_resume_and_get() already drops the runtime PM usage counter > in the error case. So a call to pm_runtime_put_sync() can be dropped. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > index c45c07840f64..5b8e1dfc458d 100644 > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > @@ -1413,11 +1413,9 @@ static int ti_sn_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > int ret; > > if (!pdata->pwm_enabled) { > - ret = pm_runtime_get_sync(pdata->dev); > - if (ret < 0) { > - pm_runtime_put_sync(pdata->dev); > + ret = pm_runtime_resume_and_get(pdata->dev); > + if (ret < 0) > return ret; > - } > } > > if (state->enabled) { Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Hi, On Thu, Nov 23, 2023 at 9:54 AM Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote: > > pm_runtime_resume_and_get() already drops the runtime PM usage counter > in the error case. So a call to pm_runtime_put_sync() can be dropped. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) Reviewed-by: Douglas Anderson <dianders@chromium.org>
Hi Uwe, Thank you for the patch. On Thu, Nov 23, 2023 at 06:54:27PM +0100, Uwe Kleine-König wrote: > pm_runtime_resume_and_get() already drops the runtime PM usage counter > in the error case. So a call to pm_runtime_put_sync() can be dropped. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> I wonder if checkpatch should warn about usage of pm_runtime_get_sync(). Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > index c45c07840f64..5b8e1dfc458d 100644 > --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c > @@ -1413,11 +1413,9 @@ static int ti_sn_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > int ret; > > if (!pdata->pwm_enabled) { > - ret = pm_runtime_get_sync(pdata->dev); > - if (ret < 0) { > - pm_runtime_put_sync(pdata->dev); > + ret = pm_runtime_resume_and_get(pdata->dev); > + if (ret < 0) > return ret; > - } > } > > if (state->enabled) {
Hi, On Thu, Nov 23, 2023 at 9:54 AM Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote: > > pm_runtime_resume_and_get() already drops the runtime PM usage counter > in the error case. So a call to pm_runtime_put_sync() can be dropped. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) Pushed this patch to drm-misc-next: c9d99c73940e drm/bridge: ti-sn65dsi86: Simplify using pm_runtime_resume_and_get()
Hello Laurent, On Wed, Nov 29, 2023 at 02:39:55AM +0200, Laurent Pinchart wrote: > On Thu, Nov 23, 2023 at 06:54:27PM +0100, Uwe Kleine-König wrote: > > pm_runtime_resume_and_get() already drops the runtime PM usage counter > > in the error case. So a call to pm_runtime_put_sync() can be dropped. > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > I wonder if checkpatch should warn about usage of pm_runtime_get_sync(). It should not warn in general. There are cases where pm_runtime_get_sync() is the right function to use. See for example commit aec488051633 ("crypto: stm32 - Properly handle pm_runtime_get failing"). Best regards Uwe
Hi Uwe, On Wed, Nov 29, 2023 at 10:51:37AM +0100, Uwe Kleine-König wrote: > On Wed, Nov 29, 2023 at 02:39:55AM +0200, Laurent Pinchart wrote: > > On Thu, Nov 23, 2023 at 06:54:27PM +0100, Uwe Kleine-König wrote: > > > pm_runtime_resume_and_get() already drops the runtime PM usage counter > > > in the error case. So a call to pm_runtime_put_sync() can be dropped. > > > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > > > I wonder if checkpatch should warn about usage of pm_runtime_get_sync(). > > It should not warn in general. There are cases where > pm_runtime_get_sync() is the right function to use. See for example Sure, the function most likely has some valid use cases (otherwise it should just be removed), but I think those are are a minority. I was just thinking out loud anyway. > commit aec488051633 ("crypto: stm32 - Properly handle pm_runtime_get > failing"). I don't know much about that device, but wouldn't the best option be to avoid resuming the device at remove time ? In any case, that's getting out of topic for the sn65dsi86 :-)
Hello Laurent, On Wed, Nov 29, 2023 at 12:11:50PM +0200, Laurent Pinchart wrote: > On Wed, Nov 29, 2023 at 10:51:37AM +0100, Uwe Kleine-König wrote: > > On Wed, Nov 29, 2023 at 02:39:55AM +0200, Laurent Pinchart wrote: > > > On Thu, Nov 23, 2023 at 06:54:27PM +0100, Uwe Kleine-König wrote: > > > > pm_runtime_resume_and_get() already drops the runtime PM usage counter > > > > in the error case. So a call to pm_runtime_put_sync() can be dropped. > > > > > > > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > > > > > I wonder if checkpatch should warn about usage of pm_runtime_get_sync(). > > > > It should not warn in general. There are cases where > > pm_runtime_get_sync() is the right function to use. See for example > > Sure, the function most likely has some valid use cases (otherwise it > should just be removed), but I think those are are a minority. I was > just thinking out loud anyway. > > > commit aec488051633 ("crypto: stm32 - Properly handle pm_runtime_get > > failing"). > > I don't know much about that device, but wouldn't the best option be to > avoid resuming the device at remove time ? In any case, that's getting > out of topic for the sn65dsi86 :-) Agreed for off-topic, I adapted the Subject to make this more obvious and added Greg and Rafael to Cc:. Without waking the device in .remove() it's harder to properly free resources. OTOH if you properly handle a failure to wake the device, you cope for most of that difficulty already anyhow. Hmm. One thing that makes this (IMHO) worse is that __device_release_driver() calls pm_runtime_put_sync() just before device_remove() (which triggers calling the driver's remove function). See https://lore.kernel.org/linux-kernel/20230511073428.10264-1-u.kleine-koenig@pengutronix.de for an earlier discussion about that topic. Best regards Uwe
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index c45c07840f64..5b8e1dfc458d 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -1413,11 +1413,9 @@ static int ti_sn_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, int ret; if (!pdata->pwm_enabled) { - ret = pm_runtime_get_sync(pdata->dev); - if (ret < 0) { - pm_runtime_put_sync(pdata->dev); + ret = pm_runtime_resume_and_get(pdata->dev); + if (ret < 0) return ret; - } } if (state->enabled) {
pm_runtime_resume_and_get() already drops the runtime PM usage counter in the error case. So a call to pm_runtime_put_sync() can be dropped. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)