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drm: rcar-du: Keep plane to CRTC associations when disabling a plane 

Changing the plane to CRTC associations requires restarting the CRTC
group, creating visible flicker. Mitigate the issue by changing plane
association only when a plane becomes enabled, not when it get disabled.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
This commit is contained in:
Laurent Pinchart 2015-04-28 18:01:45 +03:00
parent 0805861195
commit 2a57e9b5af
3 changed files with 37 additions and 21 deletions
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48
drivers/gpu/drm/rcar-du/rcar_du_crtc.c
View File

@ -208,9 +208,10 @@ static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
{
struct rcar_du_plane *planes[RCAR_DU_NUM_HW_PLANES];
unsigned int num_planes = 0;
unsigned int dptsr_planes;
unsigned int hwplanes = 0;
unsigned int prio = 0;
unsigned int i;
u32 dptsr = 0;
u32 dspr = 0;
for (i = 0; i < ARRAY_SIZE(rcrtc->group->planes); ++i) {
@ -238,37 +239,44 @@ static void rcar_du_crtc_update_planes(struct rcar_du_crtc *rcrtc)
prio -= 4;
dspr |= (index + 1) << prio;
dptsr |= DPTSR_PnDK(index) | DPTSR_PnTS(index);
hwplanes |= 1 << index;
if (plane_format(plane)->planes == 2) {
index = (index + 1) % 8;
prio -= 4;
dspr |= (index + 1) << prio;
dptsr |= DPTSR_PnDK(index) | DPTSR_PnTS(index);
hwplanes |= 1 << index;
}
}
/* Select display timing and dot clock generator 2 for planes associated
* with superposition controller 2.
/* Update the planes to display timing and dot clock generator
* associations.
*
* Updating the DPTSR register requires restarting the CRTC group,
* resulting in visible flicker. To mitigate the issue only update the
* association if needed by enabled planes. Planes being disabled will
* keep their current association.
*
* To mitigate the issue further we could pre-associate planes with
* CRTCs, either with a fixed 4/4 split, or through a module parameter.
*/
if (rcrtc->index % 2) {
/* The DPTSR register is updated when the display controller is
* stopped. We thus need to restart the DU. Once again, sorry
* for the flicker. One way to mitigate the issue would be to
* pre-associate planes with CRTCs (either with a fixed 4/4
* split, or through a module parameter). Flicker would then
* occur only if we need to break the pre-association.
*/
mutex_lock(&rcrtc->group->lock);
if (rcar_du_group_read(rcrtc->group, DPTSR) != dptsr) {
rcar_du_group_write(rcrtc->group, DPTSR, dptsr);
if (rcrtc->group->used_crtcs)
rcar_du_group_restart(rcrtc->group);
}
mutex_unlock(&rcrtc->group->lock);
mutex_lock(&rcrtc->group->lock);
dptsr_planes = rcrtc->index % 2 ? rcrtc->group->dptsr_planes | hwplanes
: rcrtc->group->dptsr_planes & ~hwplanes;
if (dptsr_planes != rcrtc->group->dptsr_planes) {
rcar_du_group_write(rcrtc->group, DPTSR,
(dptsr_planes << 16) | dptsr_planes);
rcrtc->group->dptsr_planes = dptsr_planes;
if (rcrtc->group->used_crtcs)
rcar_du_group_restart(rcrtc->group);
}
mutex_unlock(&rcrtc->group->lock);
rcar_du_group_write(rcrtc->group, rcrtc->index % 2 ? DS2PR : DS1PR,
dspr);
}

6
drivers/gpu/drm/rcar-du/rcar_du_group.c
View File

@ -85,6 +85,12 @@ static void rcar_du_group_setup(struct rcar_du_group *rgrp)
* superposition 0 to DU0 pins. DU1 pins will be configured dynamically.
*/
rcar_du_group_write(rgrp, DORCR, DORCR_PG1D_DS1 | DORCR_DPRS);
/* Apply planes to CRTCs association. */
mutex_lock(&rgrp->lock);
rcar_du_group_write(rgrp, DPTSR, (rgrp->dptsr_planes << 16) |
rgrp->dptsr_planes);
mutex_unlock(&rgrp->lock);
}
/*

4
drivers/gpu/drm/rcar-du/rcar_du_group.h
View File

@ -27,7 +27,8 @@ struct rcar_du_device;
* @index: group index
* @use_count: number of users of the group (rcar_du_group_(get|put))
* @used_crtcs: number of CRTCs currently in use
* @lock: protects the DPTSR register
* @lock: protects the dptsr_planes field and the DPTSR register
* @dptsr_planes: bitmask of planes driven by dot-clock and timing generator 1
* @planes: planes handled by the group
*/
struct rcar_du_group {
@ -39,6 +40,7 @@ struct rcar_du_group {
unsigned int used_crtcs;
struct mutex lock;
unsigned int dptsr_planes;
struct rcar_du_plane planes[RCAR_DU_NUM_KMS_PLANES];
};