| Message ID | 20210929144010.1.I773a08785666ebb236917b0c8e6c05e3de471e75@changeid (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/brdige: analogix_dp: Grab runtime PM reference for DP-AUX | expand |
On Wed, Sep 29, 2021 at 02:41:03PM -0700, Brian Norris wrote: > If the display is not enable()d, then we aren't holding a runtime PM > reference here. Thus, it's easy to accidentally cause a hang, if user > space is poking around at /dev/drm_dp_aux0 at the "wrong" time. > > Let's get the panel and PM state right before trying to talk AUX. > > Fixes: 0d97ad03f422 ("drm/bridge: analogix_dp: Remove duplicated code") > Cc: <stable@vger.kernel.org> > Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> > Signed-off-by: Brian Norris <briannorris@chromium.org> > --- > > .../gpu/drm/bridge/analogix/analogix_dp_core.c | 17 ++++++++++++++++- > 1 file changed, 16 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > index b7d2e4449cfa..a1b553904b85 100644 > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > @@ -1632,8 +1632,23 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux, > struct drm_dp_aux_msg *msg) > { > struct analogix_dp_device *dp = to_dp(aux); > + int ret, ret2; > > - return analogix_dp_transfer(dp, msg); > + ret = analogix_dp_prepare_panel(dp, true, false); > + if (ret) { > + DRM_DEV_ERROR(dp->dev, "Failed to prepare panel (%d)\n", ret); s/DRM_DEV_ERROR/drm_err/ > + return ret; > + } > + > + pm_runtime_get_sync(dp->dev); > + ret = analogix_dp_transfer(dp, msg); > + pm_runtime_put(dp->dev); > + > + ret2 = analogix_dp_prepare_panel(dp, false, false); > + if (ret2) > + DRM_DEV_ERROR(dp->dev, "Failed to unprepare panel (%d)\n", ret2); What's the reasoning for not propagating unprepare failures? I feel like that should be fair game. > + > + return ret; > } > > struct analogix_dp_device * > -- > 2.33.0.685.g46640cef36-goog >
On Fri, Oct 1, 2021 at 1:37 PM Sean Paul <sean@poorly.run> wrote: > On Wed, Sep 29, 2021 at 02:41:03PM -0700, Brian Norris wrote: > > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c > > @@ -1632,8 +1632,23 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux, > > struct drm_dp_aux_msg *msg) > > { > > struct analogix_dp_device *dp = to_dp(aux); > > + int ret, ret2; > > > > - return analogix_dp_transfer(dp, msg); > > + ret = analogix_dp_prepare_panel(dp, true, false); > > + if (ret) { > > + DRM_DEV_ERROR(dp->dev, "Failed to prepare panel (%d)\n", ret); > > s/DRM_DEV_ERROR/drm_err/ Sure. Now that I'm looking a second time, I see the header recommends this. > > + return ret; > > + } > > + > > + pm_runtime_get_sync(dp->dev); > > + ret = analogix_dp_transfer(dp, msg); > > + pm_runtime_put(dp->dev); > > + > > + ret2 = analogix_dp_prepare_panel(dp, false, false); > > + if (ret2) > > + DRM_DEV_ERROR(dp->dev, "Failed to unprepare panel (%d)\n", ret2); > > What's the reasoning for not propagating unprepare failures? I feel like that > should be fair game. I suppose the underlying reason is laziness, sorry. But a related reason is the we probably should prefer propagating the analogix_dp_transfer() error, if it's non-zero, rather than the unprepare error. That's not too hard to do though, even if it's slightly more awkward. > > + > > + return ret; > > } > > > > struct analogix_dp_device * v2 coming. Regards, Brian
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index b7d2e4449cfa..a1b553904b85 100644 --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c @@ -1632,8 +1632,23 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) { struct analogix_dp_device *dp = to_dp(aux); + int ret, ret2; - return analogix_dp_transfer(dp, msg); + ret = analogix_dp_prepare_panel(dp, true, false); + if (ret) { + DRM_DEV_ERROR(dp->dev, "Failed to prepare panel (%d)\n", ret); + return ret; + } + + pm_runtime_get_sync(dp->dev); + ret = analogix_dp_transfer(dp, msg); + pm_runtime_put(dp->dev); + + ret2 = analogix_dp_prepare_panel(dp, false, false); + if (ret2) + DRM_DEV_ERROR(dp->dev, "Failed to unprepare panel (%d)\n", ret2); + + return ret; } struct analogix_dp_device *
If the display is not enable()d, then we aren't holding a runtime PM reference here. Thus, it's easy to accidentally cause a hang, if user space is poking around at /dev/drm_dp_aux0 at the "wrong" time. Let's get the panel and PM state right before trying to talk AUX. Fixes: 0d97ad03f422 ("drm/bridge: analogix_dp: Remove duplicated code") Cc: <stable@vger.kernel.org> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> Signed-off-by: Brian Norris <briannorris@chromium.org> --- .../gpu/drm/bridge/analogix/analogix_dp_core.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)