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); + 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 *
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
linux-stable-mirror@lists.linaro.org
-
Brian Norris -
Sean Paul