| Message ID | dc7f4bc45cd6be79d19d1a4027fb6f35dfb45a03.1619191723.git.mchehab+huawei@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Kieran Bingham |
| Headers | show |
| Series | media: use pm_runtime_resume_and_get() instead of pm_runtime_get_sync() | expand |
Hi Mauro, Thanks for your work. On 2021-04-24 08:45:19 +0200, Mauro Carvalho Chehab wrote: > Commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") > added pm_runtime_resume_and_get() in order to automatically handle > dev->power.usage_count decrement on errors. > > Use the new API, in order to cleanup the error check logic. > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> > --- > drivers/media/platform/rcar-vin/rcar-csi2.c | 2 +- > drivers/media/platform/rcar-vin/rcar-dma.c | 6 ++---- > drivers/media/platform/rcar-vin/rcar-v4l2.c | 6 ++---- > 3 files changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c > index e06cd512aba2..85574765a11a 100644 > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c > @@ -408,7 +408,7 @@ static void rcsi2_enter_standby(struct rcar_csi2 *priv) > > static void rcsi2_exit_standby(struct rcar_csi2 *priv) > { > - pm_runtime_get_sync(priv->dev); > + pm_runtime_resume_and_get(priv->dev); > reset_control_deassert(priv->rstc); > } > > diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c > index f30dafbdf61c..f5f722ab1d4e 100644 > --- a/drivers/media/platform/rcar-vin/rcar-dma.c > +++ b/drivers/media/platform/rcar-vin/rcar-dma.c > @@ -1458,11 +1458,9 @@ int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel) > u32 vnmc; > int ret; > > - ret = pm_runtime_get_sync(vin->dev); > - if (ret < 0) { > - pm_runtime_put_noidle(vin->dev); > + ret = pm_runtime_resume_and_get(vin->dev); > + if (ret < 0) > return ret; > - } > > /* Make register writes take effect immediately. */ > vnmc = rvin_read(vin, VNMC_REG); > diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c > index 457a65bf6b66..b1e9f86caa5c 100644 > --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c > +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c > @@ -870,11 +870,9 @@ static int rvin_open(struct file *file) > struct rvin_dev *vin = video_drvdata(file); > int ret; > > - ret = pm_runtime_get_sync(vin->dev); > - if (ret < 0) { > - pm_runtime_put_noidle(vin->dev); > + ret = pm_runtime_resume_and_get(vin->dev); > + if (ret < 0) > return ret; > - } > > ret = mutex_lock_interruptible(&vin->lock); > if (ret) > -- > 2.30.2 >
Hi Mauro, On Sat, Apr 24, 2021 at 8:46 AM Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote: > Commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") > added pm_runtime_resume_and_get() in order to automatically handle > dev->power.usage_count decrement on errors. > > Use the new API, in order to cleanup the error check logic. > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Thanks for your patch! > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c > @@ -408,7 +408,7 @@ static void rcsi2_enter_standby(struct rcar_csi2 *priv) > > static void rcsi2_exit_standby(struct rcar_csi2 *priv) > { > - pm_runtime_get_sync(priv->dev); > + pm_runtime_resume_and_get(priv->dev); I believe this part is incorrect: on failure[*], the refcount will now be decremented, and in a subsequent call to rcsi2_enter_standby(), the refcount will be decremented again due to the call to pm_runtime_put(). [*] On e.g. R-Car SoCs, this can never fail. This is the reason why many R-Car (and SuperH) drivers never check the result of pm_runtime_get_sync(). So the refcount "imbalances" were actually introduced by the various "clean up" patches to add return value checking, which now need another round of fixing... > reset_control_deassert(priv->rstc); > } > --- a/drivers/media/platform/rcar-vin/rcar-dma.c > +++ b/drivers/media/platform/rcar-vin/rcar-dma.c > @@ -1458,11 +1458,9 @@ int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel) > u32 vnmc; > int ret; > > - ret = pm_runtime_get_sync(vin->dev); > - if (ret < 0) { > - pm_runtime_put_noidle(vin->dev); > + ret = pm_runtime_resume_and_get(vin->dev); > + if (ret < 0) > return ret; > - } This change (and the change below) is correct, as the logic before/after is equivalent. Gr{oetje,eeting}s, Geert
Em Sat, 24 Apr 2021 11:12:31 +0200 Geert Uytterhoeven <geert@linux-m68k.org> escreveu: > Hi Mauro, > > On Sat, Apr 24, 2021 at 8:46 AM Mauro Carvalho Chehab > <mchehab+huawei@kernel.org> wrote: > > Commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") > > added pm_runtime_resume_and_get() in order to automatically handle > > dev->power.usage_count decrement on errors. > > > > Use the new API, in order to cleanup the error check logic. > > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> > > Thanks for your patch! > > > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c > > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c > > @@ -408,7 +408,7 @@ static void rcsi2_enter_standby(struct rcar_csi2 *priv) > > > > static void rcsi2_exit_standby(struct rcar_csi2 *priv) > > { > > - pm_runtime_get_sync(priv->dev); > > + pm_runtime_resume_and_get(priv->dev); > > I believe this part is incorrect: on failure[*], the refcount will now > be decremented, and in a subsequent call to rcsi2_enter_standby(), the > refcount will be decremented again due to the call to pm_runtime_put(). I see your point. > [*] On e.g. R-Car SoCs, this can never fail. This is the reason why > many R-Car (and SuperH) drivers never check the result of > pm_runtime_get_sync(). So the refcount "imbalances" were actually > introduced by the various "clean up" patches to add return value > checking, which now need another round of fixing... It sounds dangerous to assume that. I'm not a PM expert, but, at least looking at drivers/base/power/runtime.c, there are two situations where the core itself will return an error, even if the PM callback never return errors[1], and more could be added in the future: if (dev->power.runtime_error) retval = -EINVAL; else if (dev->power.disable_depth > 0) retval = -EACCES; [1] see rpm_resume() function IMO, the right thing here would be to check it at resume time, and to handle it properly. > > > reset_control_deassert(priv->rstc); > > } > > > --- a/drivers/media/platform/rcar-vin/rcar-dma.c > > +++ b/drivers/media/platform/rcar-vin/rcar-dma.c > > @@ -1458,11 +1458,9 @@ int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel) > > u32 vnmc; > > int ret; > > > > - ret = pm_runtime_get_sync(vin->dev); > > - if (ret < 0) { > > - pm_runtime_put_noidle(vin->dev); > > + ret = pm_runtime_resume_and_get(vin->dev); > > + if (ret < 0) > > return ret; > > - } > > This change (and the change below) is correct, as the logic before/after > is equivalent. > > Gr{oetje,eeting}s, > > Geert > Thanks, Mauro
diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c index e06cd512aba2..85574765a11a 100644 --- a/drivers/media/platform/rcar-vin/rcar-csi2.c +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c @@ -408,7 +408,7 @@ static void rcsi2_enter_standby(struct rcar_csi2 *priv) static void rcsi2_exit_standby(struct rcar_csi2 *priv) { - pm_runtime_get_sync(priv->dev); + pm_runtime_resume_and_get(priv->dev); reset_control_deassert(priv->rstc); } diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c index f30dafbdf61c..f5f722ab1d4e 100644 --- a/drivers/media/platform/rcar-vin/rcar-dma.c +++ b/drivers/media/platform/rcar-vin/rcar-dma.c @@ -1458,11 +1458,9 @@ int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel) u32 vnmc; int ret; - ret = pm_runtime_get_sync(vin->dev); - if (ret < 0) { - pm_runtime_put_noidle(vin->dev); + ret = pm_runtime_resume_and_get(vin->dev); + if (ret < 0) return ret; - } /* Make register writes take effect immediately. */ vnmc = rvin_read(vin, VNMC_REG); diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c index 457a65bf6b66..b1e9f86caa5c 100644 --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c @@ -870,11 +870,9 @@ static int rvin_open(struct file *file) struct rvin_dev *vin = video_drvdata(file); int ret; - ret = pm_runtime_get_sync(vin->dev); - if (ret < 0) { - pm_runtime_put_noidle(vin->dev); + ret = pm_runtime_resume_and_get(vin->dev); + if (ret < 0) return ret; - } ret = mutex_lock_interruptible(&vin->lock); if (ret)
Commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") added pm_runtime_resume_and_get() in order to automatically handle dev->power.usage_count decrement on errors. Use the new API, in order to cleanup the error check logic. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> --- drivers/media/platform/rcar-vin/rcar-csi2.c | 2 +- drivers/media/platform/rcar-vin/rcar-dma.c | 6 ++---- drivers/media/platform/rcar-vin/rcar-v4l2.c | 6 ++---- 3 files changed, 5 insertions(+), 9 deletions(-)