Commit c4d79c22 authored by Dave Airlie's avatar Dave Airlie

Reinstate "drm/probe-helpers: Drop locking from poll_enable""

This reverts commit 54a07c7b,
and reinstates the original.

[airlied: this might be a bad plan for git].

commit 3846fd9b
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 8c4ccc4a
    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 c36a3254
    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).
parent b0df0b25
...@@ -115,25 +115,28 @@ static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector) ...@@ -115,25 +115,28 @@ static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
#define DRM_OUTPUT_POLL_PERIOD (10*HZ) #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 * @dev: drm_device
* *
* This function re-enables the output polling work without * This function re-enables the output polling work, after it has been
* locking the mode_config mutex. * 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 * Drivers can call this helper from their device resume implementation. It is
* called from a context where the mode_config mutex is locked * an error to call this when the output polling support has not yet been set
* already. * 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; bool poll = false;
struct drm_connector *connector; struct drm_connector *connector;
struct drm_connector_list_iter conn_iter; struct drm_connector_list_iter conn_iter;
unsigned long delay = DRM_OUTPUT_POLL_PERIOD; 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) if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
return; return;
...@@ -163,7 +166,7 @@ void drm_kms_helper_poll_enable_locked(struct drm_device *dev) ...@@ -163,7 +166,7 @@ void drm_kms_helper_poll_enable_locked(struct drm_device *dev)
if (poll) if (poll)
schedule_delayed_work(&dev->mode_config.output_poll_work, delay); 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 static enum drm_connector_status
drm_connector_detect(struct drm_connector *connector, bool force) drm_connector_detect(struct drm_connector *connector, bool force)
...@@ -290,7 +293,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector, ...@@ -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. */ /* Re-enable polling in case the global poll config changed. */
if (drm_kms_helper_poll != dev->mode_config.poll_running) 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; dev->mode_config.poll_running = drm_kms_helper_poll;
...@@ -484,8 +487,12 @@ static void output_poll_execute(struct work_struct *work) ...@@ -484,8 +487,12 @@ static void output_poll_execute(struct work_struct *work)
* This function disables the output polling work. * This function disables the output polling work.
* *
* Drivers can call this helper from their device suspend implementation. It is * 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 * not an error to call this even when output polling isn't enabled or already
* disabled. * 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) void drm_kms_helper_poll_disable(struct drm_device *dev)
{ {
...@@ -495,24 +502,6 @@ void drm_kms_helper_poll_disable(struct drm_device *dev) ...@@ -495,24 +502,6 @@ void drm_kms_helper_poll_disable(struct drm_device *dev)
} }
EXPORT_SYMBOL(drm_kms_helper_poll_disable); 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 * drm_kms_helper_poll_init - initialize and enable output polling
* @dev: drm_device * @dev: drm_device
......
...@@ -180,7 +180,7 @@ static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv) ...@@ -180,7 +180,7 @@ static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
/* Enable polling and queue hotplug re-enabling. */ /* Enable polling and queue hotplug re-enabling. */
if (hpd_disabled) { 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, mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
msecs_to_jiffies(HPD_STORM_REENABLE_DELAY)); msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
} }
...@@ -511,7 +511,7 @@ static void i915_hpd_poll_init_work(struct work_struct *work) ...@@ -511,7 +511,7 @@ static void i915_hpd_poll_init_work(struct work_struct *work)
} }
if (enabled) if (enabled)
drm_kms_helper_poll_enable_locked(dev); drm_kms_helper_poll_enable(dev);
mutex_unlock(&dev->mode_config.mutex); mutex_unlock(&dev->mode_config.mutex);
......
...@@ -73,6 +73,5 @@ extern void drm_kms_helper_hotplug_event(struct drm_device *dev); ...@@ -73,6 +73,5 @@ extern void drm_kms_helper_hotplug_event(struct drm_device *dev);
extern void drm_kms_helper_poll_disable(struct drm_device *dev); extern void drm_kms_helper_poll_disable(struct drm_device *dev);
extern void drm_kms_helper_poll_enable(struct drm_device *dev); extern void drm_kms_helper_poll_enable(struct drm_device *dev);
extern void drm_kms_helper_poll_enable_locked(struct drm_device *dev);
#endif #endif
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