| Message ID | 20220420004949.20508-1-linmq006@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/vc4: Fix pm_runtime_get_sync() usage | expand |
On Wed, Apr 20, 2022 at 12:49:48AM +0000, Miaoqian Lin wrote: > If the device is already in a runtime PM enabled state > pm_runtime_get_sync() will return 1, so a test for negative > value should be used to check for errors. > > Also, we need to call pm_runtime_put_noidle() when pm_runtime_get_sync() > fails, so use pm_runtime_resume_and_get() instead. this function > will handle this. > > Fixes: 4078f5757144 ("drm/vc4: Add DSI driver") > Signed-off-by: Miaoqian Lin <linmq006@gmail.com> > --- > change in v2: > - switch to pm_runtime_resume_and_get() to fix refcount leak. > --- > drivers/gpu/drm/vc4/vc4_dsi.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c > index 752f921735c6..9d7ffaf6bc70 100644 > --- a/drivers/gpu/drm/vc4/vc4_dsi.c > +++ b/drivers/gpu/drm/vc4/vc4_dsi.c > @@ -846,8 +846,8 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder) > unsigned long phy_clock; > int ret; > > - ret = pm_runtime_get_sync(dev); > - if (ret) { > + ret = pm_runtime_resume_and_get(dev); > + if (ret < 0) { pm_runtime_resume_and_get will return 0 on success, so the previous check was correct Maxime
On 2022/4/20 15:51, Maxime Ripard wrote: > On Wed, Apr 20, 2022 at 12:49:48AM +0000, Miaoqian Lin wrote: >> If the device is already in a runtime PM enabled state >> pm_runtime_get_sync() will return 1, so a test for negative >> value should be used to check for errors. >> >> Also, we need to call pm_runtime_put_noidle() when pm_runtime_get_sync() >> fails, so use pm_runtime_resume_and_get() instead. this function >> will handle this. >> >> Fixes: 4078f5757144 ("drm/vc4: Add DSI driver") >> Signed-off-by: Miaoqian Lin <linmq006@gmail.com> >> --- >> change in v2: >> - switch to pm_runtime_resume_and_get() to fix refcount leak. >> --- >> drivers/gpu/drm/vc4/vc4_dsi.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c >> index 752f921735c6..9d7ffaf6bc70 100644 >> --- a/drivers/gpu/drm/vc4/vc4_dsi.c >> +++ b/drivers/gpu/drm/vc4/vc4_dsi.c >> @@ -846,8 +846,8 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder) >> unsigned long phy_clock; >> int ret; >> >> - ret = pm_runtime_get_sync(dev); >> - if (ret) { >> + ret = pm_runtime_resume_and_get(dev); >> + if (ret < 0) { > pm_runtime_resume_and_get will return 0 on success, so the previous check was correct previous check is for pm_runtime_get_sync() not for pm_runtime_resume_and_get (), I switch to pm_runtime_resume_and_get() to fix the refcount leak bug at the same time. Sure it's ok to use check if(ret) to check the retval, I just follow a more common way for usage of pm_runtime_resume_and_get() in the codebase—— check ret<0 Since pm_runtime_resume_and_get() return negative error code. > Maxime
On Wed, Apr 20, 2022 at 04:05:35PM +0800, Miaoqian Lin wrote: > > On 2022/4/20 15:51, Maxime Ripard wrote: > > On Wed, Apr 20, 2022 at 12:49:48AM +0000, Miaoqian Lin wrote: > >> If the device is already in a runtime PM enabled state > >> pm_runtime_get_sync() will return 1, so a test for negative > >> value should be used to check for errors. > >> > >> Also, we need to call pm_runtime_put_noidle() when pm_runtime_get_sync() > >> fails, so use pm_runtime_resume_and_get() instead. this function > >> will handle this. > >> > >> Fixes: 4078f5757144 ("drm/vc4: Add DSI driver") > >> Signed-off-by: Miaoqian Lin <linmq006@gmail.com> > >> --- > >> change in v2: > >> - switch to pm_runtime_resume_and_get() to fix refcount leak. > >> --- > >> drivers/gpu/drm/vc4/vc4_dsi.c | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c > >> index 752f921735c6..9d7ffaf6bc70 100644 > >> --- a/drivers/gpu/drm/vc4/vc4_dsi.c > >> +++ b/drivers/gpu/drm/vc4/vc4_dsi.c > >> @@ -846,8 +846,8 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder) > >> unsigned long phy_clock; > >> int ret; > >> > >> - ret = pm_runtime_get_sync(dev); > >> - if (ret) { > >> + ret = pm_runtime_resume_and_get(dev); > >> + if (ret < 0) { > > pm_runtime_resume_and_get will return 0 on success, so the previous check was correct > > previous check is for pm_runtime_get_sync() not for pm_runtime_resume_and_get (), > > I switch to pm_runtime_resume_and_get() to fix the refcount leak bug at the same time. > > Sure it's ok to use check if(ret) to check the retval, I just follow a more common way > > for usage of pm_runtime_resume_and_get() in the codebase—— check ret<0 > > Since pm_runtime_resume_and_get() return negative error code. If it ain't broke, don't fix it. The previous condition was working perfectly fine to catch the errors from pm_runtime_resume_and_get, there's no reason to change it. Maxime
diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c index 752f921735c6..9d7ffaf6bc70 100644 --- a/drivers/gpu/drm/vc4/vc4_dsi.c +++ b/drivers/gpu/drm/vc4/vc4_dsi.c @@ -846,8 +846,8 @@ static void vc4_dsi_encoder_enable(struct drm_encoder *encoder) unsigned long phy_clock; int ret; - ret = pm_runtime_get_sync(dev); - if (ret) { + ret = pm_runtime_resume_and_get(dev); + if (ret < 0) { DRM_ERROR("Failed to runtime PM enable on DSI%d\n", dsi->variant->port); return; }
If the device is already in a runtime PM enabled state pm_runtime_get_sync() will return 1, so a test for negative value should be used to check for errors. Also, we need to call pm_runtime_put_noidle() when pm_runtime_get_sync() fails, so use pm_runtime_resume_and_get() instead. this function will handle this. Fixes: 4078f5757144 ("drm/vc4: Add DSI driver") Signed-off-by: Miaoqian Lin <linmq006@gmail.com> --- change in v2: - switch to pm_runtime_resume_and_get() to fix refcount leak. --- drivers/gpu/drm/vc4/vc4_dsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)