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Commit 94b83957 authored by Rodrigo Vivi's avatar Rodrigo Vivi Committed by Daniel Vetter
Browse files

drm/i915: Introduce FBC DocBook. 



No functional changes.

v2 (Paulo): Rebase.
v3: Accept Daniel's suggestions:
    * remove unclear and duplicated explanation.
    * remove marketing like doc and replace by a simple one.
    * remove bdw_fbc_sw_flush documentation.

Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent c0beefd2

Documentation/DocBook/drm.tmpl

+5 −0
Original line number Diff line number Diff line
@@ -3924,6 +3924,11 @@ int num_ioctls;</synopsis> 
	<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>Frame Buffer Compression (FBC)</title>

!Pdrivers/gpu/drm/i915/intel_fbc.c Frame Buffer Compression (FBC)

!Idrivers/gpu/drm/i915/intel_fbc.c

      </sect2>

      <sect2>

        <title>DPIO</title>

drivers/gpu/drm/i915/intel_fbc.c

+35 −9
Original line number Diff line number Diff line
@@ -21,20 +21,26 @@ 
 * DEALINGS IN THE SOFTWARE.

 */



#include "intel_drv.h"

#include "i915_drv.h"



/* FBC, or Frame Buffer Compression, is a technique employed to compress the

 * framebuffer contents in-memory, aiming at reducing the required bandwidth

 * during in-memory transfers and, therefore, reduce the power packet.

/**

 * DOC: Frame Buffer Compression (FBC)

 *

 * FBC tries to save memory bandwidth (and so power consumption) by

 * compressing the amount of memory used by the display. It is total

 * transparent to user space and completely handled in the kernel.

 *

 * The benefits of FBC are mostly visible with solid backgrounds and

 * variation-less patterns.

 * variation-less patterns. It comes from keeping the memory footprint small

 * and having fewer memory pages opened and accessed for refreshing the display.

 *

 * FBC-related functionality can be enabled by the means of the

 * i915.i915_fbc_enable parameter

 * i915 is responsible to reserve stolen memory for FBC and configure its

 * offset on proper registers. The hardware takes care of all

 * compress/decompress. However there are many known cases where we have to

 * forcibly disable it to allow proper screen updates.

 */



#include "intel_drv.h"

#include "i915_drv.h"



static void i8xx_fbc_disable(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -318,6 +324,14 @@ static void gen7_fbc_enable(struct drm_crtc *crtc) 
	DRM_DEBUG_KMS("enabled fbc on plane %c\n", plane_name(intel_crtc->plane));

}



/**

 * intel_fbc_enabled - Is FBC enabled?

 * @dev: the drm_device

 *

 * This function is used to verify the current state of FBC.

 * FIXME: This should be tracked in the plane config eventually

 *        instead of queried at runtime for most callers.

 */

bool intel_fbc_enabled(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -429,6 +443,12 @@ static void intel_fbc_enable(struct drm_crtc *crtc) 
	schedule_delayed_work(&work->work, msecs_to_jiffies(50));

}



/**

 * intel_fbc_disable - disable FBC

 * @dev: the drm_device

 *

 * This function disables FBC.

 */

void intel_fbc_disable(struct drm_device *dev)

{

	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -643,6 +663,12 @@ void intel_fbc_update(struct drm_device *dev) 
	i915_gem_stolen_cleanup_compression(dev);

}



/**

 * intel_fbc_init - Initialize FBC

 * @dev_priv: the i915 device

 *

 * This function might be called during PM init process.

 */

void intel_fbc_init(struct drm_i915_private *dev_priv)

{

	if (!HAS_FBC(dev_priv)) {