| Message ID | 1487985916-29450-1-git-send-email-john.stultz@linaro.org |
|---|---|
| State | New |
| Headers | show |
Hi John, The patch seems good to me, except one minus comment. Maybe change fb_lock to fbdev_lock would be better. Thanks, -xinliang On 2017/2/25 9:25, John Stultz wrote: > In some cases I've been seeing a race where two framebuffers > would be initialized, as kirin_fbdev_output_poll_changed() > might get called quickly in succession, resulting in the > initialization happening twice. This could cause the system > to boot up with a blank screen. > > This patch adds a simple mutex to serialize it and seems to > avoid the race. > > Suggestions or feedback would be greatly appreciated! > > Cc: Xinliang Liu <z.liuxinliang@hisilicon.com> > Cc: Rongrong Zou <zourongrong@gmail.com> > Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com> > Cc: Chen Feng <puck.chen@hisilicon.com> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > Cc: Sean Paul <seanpaul@chromium.org> > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: John Stultz <john.stultz@linaro.org> > --- > drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 4 ++++ > drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h | 1 + > 2 files changed, 5 insertions(+) > > diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c > index 7ec93ae..b83556a 100644 > --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c > +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c > @@ -55,6 +55,7 @@ static void kirin_fbdev_output_poll_changed(struct drm_device *dev) > { > struct kirin_drm_private *priv = dev->dev_private; > > + mutex_lock(&priv->fb_lock); > if (priv->fbdev) { > drm_fbdev_cma_hotplug_event(priv->fbdev); > } else { > @@ -63,6 +64,7 @@ static void kirin_fbdev_output_poll_changed(struct drm_device *dev) > if (IS_ERR(priv->fbdev)) > priv->fbdev = NULL; > } > + mutex_unlock(&priv->fb_lock); > } > #endif > > @@ -95,6 +97,8 @@ static int kirin_drm_kms_init(struct drm_device *dev) > if (!priv) > return -ENOMEM; > > + mutex_init(&priv->fb_lock); > + > dev->dev_private = priv; > dev_set_drvdata(dev->dev, dev); > > diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h > index 7f60c649..9b6d2b1 100644 > --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h > +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h > @@ -23,6 +23,7 @@ struct kirin_drm_private { > #ifdef CONFIG_DRM_FBDEV_EMULATION > struct drm_fbdev_cma *fbdev; > #endif > + struct mutex fb_lock; > }; > > extern const struct kirin_dc_ops ade_dc_ops;
On 2017/2/25 9:39, liuxinliang wrote: > Hi John, > > The patch seems good to me, except one minus comment. > Maybe change fb_lock to fbdev_lock would be better. > > Thanks, > -xinliang > > On 2017/2/25 9:25, John Stultz wrote: >> In some cases I've been seeing a race where two framebuffers >> would be initialized, as kirin_fbdev_output_poll_changed() >> might get called quickly in succession, resulting in the >> initialization happening twice. This could cause the system >> to boot up with a blank screen. >> >> This patch adds a simple mutex to serialize it and seems to >> avoid the race. >> >> Suggestions or feedback would be greatly appreciated! >> >> Cc: Xinliang Liu <z.liuxinliang@hisilicon.com> >> Cc: Rongrong Zou <zourongrong@gmail.com> >> Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com> >> Cc: Chen Feng <puck.chen@hisilicon.com> >> Cc: David Airlie <airlied@linux.ie> >> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> >> Cc: Sean Paul <seanpaul@chromium.org> >> Cc: dri-devel@lists.freedesktop.org >> Signed-off-by: John Stultz <john.stultz@linaro.org> >> --- >> drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 4 ++++ >> drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h | 1 + >> 2 files changed, 5 insertions(+) >> >> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c >> b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c >> index 7ec93ae..b83556a 100644 >> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c >> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c >> @@ -55,6 +55,7 @@ static void kirin_fbdev_output_poll_changed(struct >> drm_device *dev) >> { >> struct kirin_drm_private *priv = dev->dev_private; >> + mutex_lock(&priv->fb_lock); >> if (priv->fbdev) { >> drm_fbdev_cma_hotplug_event(priv->fbdev); >> } else { >> @@ -63,6 +64,7 @@ static void kirin_fbdev_output_poll_changed(struct >> drm_device *dev) >> if (IS_ERR(priv->fbdev)) >> priv->fbdev = NULL; >> } >> + mutex_unlock(&priv->fb_lock); >> } >> #endif >> @@ -95,6 +97,8 @@ static int kirin_drm_kms_init(struct drm_device >> *dev) >> if (!priv) >> return -ENOMEM; >> + mutex_init(&priv->fb_lock); And put this line in CONFIG_DRM_FBDEV_EMULATION >> + >> dev->dev_private = priv; >> dev_set_drvdata(dev->dev, dev); >> diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h >> b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h >> index 7f60c649..9b6d2b1 100644 >> --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h >> +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h >> @@ -23,6 +23,7 @@ struct kirin_drm_private { >> #ifdef CONFIG_DRM_FBDEV_EMULATION >> struct drm_fbdev_cma *fbdev; >> #endif >> + struct mutex fb_lock; And here. -xinliang >> }; >> extern const struct kirin_dc_ops ade_dc_ops; >
On Sat, Feb 25, 2017 at 11:36 AM, Daniel Vetter <daniel@ffwll.ch> wrote: > On Fri, Feb 24, 2017 at 05:25:16PM -0800, John Stultz wrote: >> In some cases I've been seeing a race where two framebuffers >> would be initialized, as kirin_fbdev_output_poll_changed() >> might get called quickly in succession, resulting in the >> initialization happening twice. This could cause the system >> to boot up with a blank screen. >> >> This patch adds a simple mutex to serialize it and seems to >> avoid the race. >> >> Suggestions or feedback would be greatly appreciated! > > I feel a bit like a broken record, but: > > Instead of reinventing broken delayed fbdev setup everywhere, can we > polish Thierry's patches to move that into the fbdev helpers in the core? > hisilicon isn't the only driver the (re)invents this weel, it'd be really > awesome if we could fix this bug just once ... > > For reference, the patches: > > http://markmail.org/message/d3jc4vebkndtvlkf#query:+page:1+mid:d3jc4vebkndtvlkf+state:results Thanks for the pointer here, and apologies, I really am not very deep into or do that much following DRM development. I just am chasing bugs on my board and trying to fix them up, so I wasn't aware this was something brought up before. > I guess Thierry got sidetracked on these, but except for a bit of locking > scheme polish I think they've been mostly ready. Shouldn't be much work to > refresh them, hunt for other new drivers reinventing this wheel, do the > locking polish maybe and then get them landed. I'll take a look at it and see what I can sort out. thanks -john
diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c index 7ec93ae..b83556a 100644 --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c @@ -55,6 +55,7 @@ static void kirin_fbdev_output_poll_changed(struct drm_device *dev) { struct kirin_drm_private *priv = dev->dev_private; + mutex_lock(&priv->fb_lock); if (priv->fbdev) { drm_fbdev_cma_hotplug_event(priv->fbdev); } else { @@ -63,6 +64,7 @@ static void kirin_fbdev_output_poll_changed(struct drm_device *dev) if (IS_ERR(priv->fbdev)) priv->fbdev = NULL; } + mutex_unlock(&priv->fb_lock); } #endif @@ -95,6 +97,8 @@ static int kirin_drm_kms_init(struct drm_device *dev) if (!priv) return -ENOMEM; + mutex_init(&priv->fb_lock); + dev->dev_private = priv; dev_set_drvdata(dev->dev, dev); diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h index 7f60c649..9b6d2b1 100644 --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h @@ -23,6 +23,7 @@ struct kirin_drm_private { #ifdef CONFIG_DRM_FBDEV_EMULATION struct drm_fbdev_cma *fbdev; #endif + struct mutex fb_lock; }; extern const struct kirin_dc_ops ade_dc_ops;
In some cases I've been seeing a race where two framebuffers would be initialized, as kirin_fbdev_output_poll_changed() might get called quickly in succession, resulting in the initialization happening twice. This could cause the system to boot up with a blank screen. This patch adds a simple mutex to serialize it and seems to avoid the race. Suggestions or feedback would be greatly appreciated! Cc: Xinliang Liu <z.liuxinliang@hisilicon.com> Cc: Rongrong Zou <zourongrong@gmail.com> Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com> Cc: Chen Feng <puck.chen@hisilicon.com> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <seanpaul@chromium.org> Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz <john.stultz@linaro.org> --- drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 4 ++++ drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.h | 1 + 2 files changed, 5 insertions(+) -- 2.7.4