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drm: Add dev->vblank_disable_immediate flag

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Add a flag to drm_device which will cause the vblank code to bypass the
disable timer and always disable the vblank interrupt immediately when
the last reference is dropped.

v2: Add some notes about the flag to the kernel doc

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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 2014-08-06 14:49:54 +03:00 committed by Daniel Vetter
parent 4ed0ce3d0b
commit 00185e6670
3 changed files with 17 additions and 1 deletions
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6
Documentation/DocBook/drm.tmpl
View File

@ -3387,6 +3387,12 @@ void (*disable_vblank) (struct drm_device *dev, int crtc);</synopsis>
module parameter or the <varname>drm_vblank_offdelay</varname> global
variable and expressed in milliseconds. Its default value is 5000 ms.
Zero means never disable, and a negative value means disable immediately.
Drivers may override the behaviour by setting the
<structname>drm_device</structname>
<structfield>vblank_disable_immediate</structfield> flag, which when set
causes vblank interrupts to be disabled immediately regardless of the
drm_vblank_offdelay value. The flag should only be set if there's a
properly working hardware vblank counter present.
</para>
<para>
When a vertical blanking interrupt occurs drivers only need to call the

2
drivers/gpu/drm/drm_irq.c
View File

@ -994,7 +994,7 @@ void drm_vblank_put(struct drm_device *dev, int crtc)
/* Last user schedules interrupt disable */
if (atomic_dec_and_test(&vblank->refcount)) {
if (drm_vblank_offdelay < 0)
if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
vblank_disable_fn((unsigned long)vblank);
else if (drm_vblank_offdelay > 0)
mod_timer(&vblank->disable_timer,

10
include/drm/drmP.h
View File

@ -1074,6 +1074,16 @@ struct drm_device {
*/
bool vblank_disable_allowed;
/*
* If true, vblank interrupt will be disabled immediately when the
* refcount drops to zero, as opposed to via the vblank disable
* timer.
* This can be set to true it the hardware has a working vblank
* counter and the driver uses drm_vblank_on() and drm_vblank_off()
* appropriately.
*/
bool vblank_disable_immediate;
/* array of size num_crtcs */
struct drm_vblank_crtc *vblank;