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drm/i915: Add comments explaining the vdd on/off functions

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Jani wanted some comments to explain why we call certain vdd on/off
functions in certain places.

v2: Make the comments more thorough (Imre)

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2014-09-04 14:55:31 +03:00 committed by Daniel Vetter
parent 08aff3fe26
commit 951468f331
1 changed files with 35 additions and 0 deletions
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35
drivers/gpu/drm/i915/intel_dp.c
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@ -1354,6 +1354,11 @@ static u32 ironlake_get_pp_control(struct intel_dp *intel_dp)
return control;
}
/*
* Must be paired with edp_panel_vdd_off().
* Must hold pps_mutex around the whole on/off sequence.
* Can be nested with intel_edp_panel_vdd_{on,off}() calls.
*/
static bool edp_panel_vdd_on(struct intel_dp *intel_dp)
{
struct drm_device *dev = intel_dp_to_dev(intel_dp);
@ -1404,6 +1409,13 @@ static bool edp_panel_vdd_on(struct intel_dp *intel_dp)
return need_to_disable;
}
/*
* Must be paired with intel_edp_panel_vdd_off() or
* intel_edp_panel_off().
* Nested calls to these functions are not allowed since
* we drop the lock. Caller must use some higher level
* locking to prevent nested calls from other threads.
*/
void intel_edp_panel_vdd_on(struct intel_dp *intel_dp)
{
bool vdd;
@ -1482,6 +1494,11 @@ static void edp_panel_vdd_schedule_off(struct intel_dp *intel_dp)
schedule_delayed_work(&intel_dp->panel_vdd_work, delay);
}
/*
* Must be paired with edp_panel_vdd_on().
* Must hold pps_mutex around the whole on/off sequence.
* Can be nested with intel_edp_panel_vdd_{on,off}() calls.
*/
static void edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
{
struct drm_i915_private *dev_priv =
@ -1502,6 +1519,12 @@ static void edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
edp_panel_vdd_schedule_off(intel_dp);
}
/*
* Must be paired with intel_edp_panel_vdd_on().
* Nested calls to these functions are not allowed since
* we drop the lock. Caller must use some higher level
* locking to prevent nested calls from other threads.
*/
static void intel_edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
{
if (!is_edp(intel_dp))
@ -4373,6 +4396,10 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
drm_encoder_cleanup(encoder);
if (is_edp(intel_dp)) {
cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
/*
* vdd might still be enabled do to the delayed vdd off.
* Make sure vdd is actually turned off here.
*/
pps_lock(intel_dp);
edp_panel_vdd_off_sync(intel_dp);
pps_unlock(intel_dp);
@ -4392,6 +4419,10 @@ static void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
if (!is_edp(intel_dp))
return;
/*
* vdd might still be enabled do to the delayed vdd off.
* Make sure vdd is actually turned off here.
*/
pps_lock(intel_dp);
edp_panel_vdd_off_sync(intel_dp);
pps_unlock(intel_dp);
@ -5095,6 +5126,10 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
drm_dp_aux_unregister(&intel_dp->aux);
if (is_edp(intel_dp)) {
cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
/*
* vdd might still be enabled do to the delayed vdd off.
* Make sure vdd is actually turned off here.
*/
pps_lock(intel_dp);
edp_panel_vdd_off_sync(intel_dp);
pps_unlock(intel_dp);