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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: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Rodrigo Vivi 2014-12-08 06:46:31 -08:00 committed by Daniel Vetter
parent c0beefd29f
commit 94b8395755
2 changed files with 40 additions and 9 deletions
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5
Documentation/DocBook/drm.tmpl
View File

@ -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>

44
drivers/gpu/drm/i915/intel_fbc.c
View File

@ -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 @@ out_disable:
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)) {