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author | Dave Airlie <airlied@redhat.com> | 2017-01-27 12:04:08 +1000 |
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committer | Dave Airlie <airlied@redhat.com> | 2017-01-27 12:04:08 +1000 |
commit | c4d79c22015564a9d922715434a0ec09d1deee30 (patch) | |
tree | 0244663e07ce8575d6060d0f1dae9d8fef30e829 /drivers/gpu/drm | |
parent | b0df0b251b25b0bf89ef3e518330fcac300add86 (diff) | |
download | linux-stable-c4d79c22015564a9d922715434a0ec09d1deee30.tar.gz linux-stable-c4d79c22015564a9d922715434a0ec09d1deee30.tar.bz2 linux-stable-c4d79c22015564a9d922715434a0ec09d1deee30.zip |
Reinstate "drm/probe-helpers: Drop locking from poll_enable""
This reverts commit 54a07c7bb0da0343734c78212bbe9f3735394962,
and reinstates the original.
[airlied: this might be a bad plan for git].
commit 3846fd9b86001bea171943cc3bb9222cb6da6b42
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed Jan 11 10:01:17 2017 +0100
drm/probe-helpers: Drop locking from poll_enable
It was only needed to protect the connector_list walking, see
commit 8c4ccc4ab6f64e859d4ff8d7c02c2ed2e956e07f
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Thu Jul 9 23:44:26 2015 +0200
drm/probe-helper: Grab mode_config.mutex in poll_init/enable
Unfortunately the commit message of that patch fails to mention that
the new locking check was for the connector_list.
But that requirement disappeared in
commit c36a3254f7857f1ad9badbe3578ccc92be541a8e
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Thu Dec 15 16:58:43 2016 +0100
drm: Convert all helpers to drm_connector_list_iter
and so we can drop this again.
This fixes a locking inversion on nouveau, where the rpm code needs to
re-enable. But in other places the rpm_get() calls are nested within
the big modeset locks.
While at it, also improve the kerneldoc for these two functions a
notch.
v2: Update the kerneldoc even more to explain that these functions
can't be called concurrently, or bad things happen (Chris).
Diffstat (limited to 'drivers/gpu/drm')
-rw-r--r-- | drivers/gpu/drm/drm_probe_helper.c | 51 | ||||
-rw-r--r-- | drivers/gpu/drm/i915/intel_hotplug.c | 4 |
2 files changed, 22 insertions, 33 deletions
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 79519e4983c7..041a5504780f 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -115,25 +115,28 @@ static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector) #define DRM_OUTPUT_POLL_PERIOD (10*HZ) /** - * drm_kms_helper_poll_enable_locked - re-enable output polling. + * drm_kms_helper_poll_enable - re-enable output polling. * @dev: drm_device * - * This function re-enables the output polling work without - * locking the mode_config mutex. + * This function re-enables the output polling work, after it has been + * temporarily disabled using drm_kms_helper_poll_disable(), for example over + * suspend/resume. * - * This is like drm_kms_helper_poll_enable() however it is to be - * called from a context where the mode_config mutex is locked - * already. + * Drivers can call this helper from their device resume implementation. It is + * an error to call this when the output polling support has not yet been set + * up. + * + * Note that calls to enable and disable polling must be strictly ordered, which + * is automatically the case when they're only call from suspend/resume + * callbacks. */ -void drm_kms_helper_poll_enable_locked(struct drm_device *dev) +void drm_kms_helper_poll_enable(struct drm_device *dev) { bool poll = false; struct drm_connector *connector; struct drm_connector_list_iter conn_iter; unsigned long delay = DRM_OUTPUT_POLL_PERIOD; - WARN_ON(!mutex_is_locked(&dev->mode_config.mutex)); - if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll) return; @@ -163,7 +166,7 @@ void drm_kms_helper_poll_enable_locked(struct drm_device *dev) if (poll) schedule_delayed_work(&dev->mode_config.output_poll_work, delay); } -EXPORT_SYMBOL(drm_kms_helper_poll_enable_locked); +EXPORT_SYMBOL(drm_kms_helper_poll_enable); static enum drm_connector_status drm_connector_detect(struct drm_connector *connector, bool force) @@ -290,7 +293,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector, /* Re-enable polling in case the global poll config changed. */ if (drm_kms_helper_poll != dev->mode_config.poll_running) - drm_kms_helper_poll_enable_locked(dev); + drm_kms_helper_poll_enable(dev); dev->mode_config.poll_running = drm_kms_helper_poll; @@ -484,8 +487,12 @@ out: * This function disables the output polling work. * * Drivers can call this helper from their device suspend implementation. It is - * not an error to call this even when output polling isn't enabled or arlready - * disabled. + * not an error to call this even when output polling isn't enabled or already + * disabled. Polling is re-enabled by calling drm_kms_helper_poll_enable(). + * + * Note that calls to enable and disable polling must be strictly ordered, which + * is automatically the case when they're only call from suspend/resume + * callbacks. */ void drm_kms_helper_poll_disable(struct drm_device *dev) { @@ -496,24 +503,6 @@ void drm_kms_helper_poll_disable(struct drm_device *dev) EXPORT_SYMBOL(drm_kms_helper_poll_disable); /** - * drm_kms_helper_poll_enable - re-enable output polling. - * @dev: drm_device - * - * This function re-enables the output polling work. - * - * Drivers can call this helper from their device resume implementation. It is - * an error to call this when the output polling support has not yet been set - * up. - */ -void drm_kms_helper_poll_enable(struct drm_device *dev) -{ - mutex_lock(&dev->mode_config.mutex); - drm_kms_helper_poll_enable_locked(dev); - mutex_unlock(&dev->mode_config.mutex); -} -EXPORT_SYMBOL(drm_kms_helper_poll_enable); - -/** * drm_kms_helper_poll_init - initialize and enable output polling * @dev: drm_device * diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c index 3d546c019de0..b62e3f8ad415 100644 --- a/drivers/gpu/drm/i915/intel_hotplug.c +++ b/drivers/gpu/drm/i915/intel_hotplug.c @@ -180,7 +180,7 @@ static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv) /* Enable polling and queue hotplug re-enabling. */ if (hpd_disabled) { - drm_kms_helper_poll_enable_locked(dev); + drm_kms_helper_poll_enable(dev); mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work, msecs_to_jiffies(HPD_STORM_REENABLE_DELAY)); } @@ -511,7 +511,7 @@ static void i915_hpd_poll_init_work(struct work_struct *work) } if (enabled) - drm_kms_helper_poll_enable_locked(dev); + drm_kms_helper_poll_enable(dev); mutex_unlock(&dev->mode_config.mutex); |