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drm/i915: Add PSR docbook 

Let's document PSR a bit. No functional changes.

v2: Add actual DocBook entry and accept Daniel's improvements.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Rodrigo Vivi 2014-11-14 08:52:29 -08:00 committed by Daniel Vetter
parent 0bc12bcb1b
commit b2b89f55df
2 changed files with 78 additions and 0 deletions
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5
Documentation/DocBook/drm.tmpl
View File

@ -3891,6 +3891,11 @@ int num_ioctls;</synopsis>
<title>High Definition Audio</title>
!Pdrivers/gpu/drm/i915/intel_audio.c High Definition Audio over HDMI and Display Port
!Idrivers/gpu/drm/i915/intel_audio.c
</sect2>
<sect2>
<title>Panel Self Refresh PSR (PSR/SRD)</title>
!Pdrivers/gpu/drm/i915/intel_psr.c Panel Self Refresh (PSR/SRD)
!Idrivers/gpu/drm/i915/intel_psr.c
</sect2>
<sect2>
<title>DPIO</title>

73
drivers/gpu/drm/i915/intel_psr.c
View File

@ -21,6 +21,36 @@
* DEALINGS IN THE SOFTWARE.
*/
/**
* DOC: Panel Self Refresh (PSR/SRD)
*
* Since Haswell Display controller supports Panel Self-Refresh on display
* panels witch have a remote frame buffer (RFB) implemented according to PSR
* spec in eDP1.3. PSR feature allows the display to go to lower standby states
* when system is idle but display is on as it eliminates display refresh
* request to DDR memory completely as long as the frame buffer for that
* display is unchanged.
*
* Panel Self Refresh must be supported by both Hardware (source) and
* Panel (sink).
*
* PSR saves power by caching the framebuffer in the panel RFB, which allows us
* to power down the link and memory controller. For DSI panels the same idea
* is called "manual mode".
*
* The implementation uses the hardware-based PSR support which automatically
* enters/exits self-refresh mode. The hardware takes care of sending the
* required DP aux message and could even retrain the link (that part isn't
* enabled yet though). The hardware also keeps track of any frontbuffer
* changes to know when to exit self-refresh mode again. Unfortunately that
* part doesn't work too well, hence why the i915 PSR support uses the
* software frontbuffer tracking to make sure it doesn't miss a screen
* update. For this integration intel_psr_invalidate() and intel_psr_flush()
* get called by the frontbuffer tracking code. Note that because of locking
* issues the self-refresh re-enable code is done from a work queue, which
* must be correctly synchronized/cancelled when shutting down the pipe."
*/
#include <drm/drmP.h>
#include "intel_drv.h"
@ -217,6 +247,12 @@ static void intel_psr_do_enable(struct intel_dp *intel_dp)
dev_priv->psr.active = true;
}
/**
* intel_psr_enable - Enable PSR
* @intel_dp: Intel DP
*
* This function can only be called after the pipe is fully trained and enabled.
*/
void intel_psr_enable(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@ -258,6 +294,12 @@ void intel_psr_enable(struct intel_dp *intel_dp)
mutex_unlock(&dev_priv->psr.lock);
}
/**
* intel_psr_disable - Disable PSR
* @intel_dp: Intel DP
*
* This function needs to be called before disabling pipe.
*/
void intel_psr_disable(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@ -342,6 +384,18 @@ static void intel_psr_exit(struct drm_device *dev)
}
/**
* intel_psr_invalidate - Invalidade PSR
* @dev: DRM device
* @frontbuffer_bits: frontbuffer plane tracking bits
*
* Since the hardware frontbuffer tracking has gaps we need to integrate
* with the software frontbuffer tracking. This function gets called every
* time frontbuffer rendering starts and a buffer gets dirtied. PSR must be
* disabled if the frontbuffer mask contains a buffer relevant to PSR.
*
* Dirty frontbuffers relevant to PSR are tracked in busy_frontbuffer_bits."
*/
void intel_psr_invalidate(struct drm_device *dev,
unsigned frontbuffer_bits)
{
@ -366,6 +420,18 @@ void intel_psr_invalidate(struct drm_device *dev,
mutex_unlock(&dev_priv->psr.lock);
}
/**
* intel_psr_flush - Flush PSR
* @dev: DRM device
* @frontbuffer_bits: frontbuffer plane tracking bits
*
* Since the hardware frontbuffer tracking has gaps we need to integrate
* with the software frontbuffer tracking. This function gets called every
* time frontbuffer rendering has completed and flushed out to memory. PSR
* can be enabled again if no other frontbuffer relevant to PSR is dirty.
*
* Dirty frontbuffers relevant to PSR are tracked in busy_frontbuffer_bits.
*/
void intel_psr_flush(struct drm_device *dev,
unsigned frontbuffer_bits)
{
@ -399,6 +465,13 @@ void intel_psr_flush(struct drm_device *dev,
mutex_unlock(&dev_priv->psr.lock);
}
/**
* intel_psr_init - Init basic PSR work and mutex.
* @dev: DRM device
*
* This function is called only once at driver load to initialize basic
* PSR stuff.
*/
void intel_psr_init(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;