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drm/radeon: Provide page_flip_target hook
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Now we can program a flip during a vertical blank period, if it's the
one targeted by the flip (or a later one). This allows simplifying
radeon_flip_work_func considerably.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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Michel Dänzer authored and Alex Deucher committed Aug 10, 2016
1 parent 3fd4b75 commit b8fc75c
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Showing 2 changed files with 25 additions and 65 deletions.
1 change: 1 addition & 0 deletions drivers/gpu/drm/radeon/radeon.h
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Original file line number Diff line number Diff line change
Expand Up @@ -742,6 +742,7 @@ struct radeon_flip_work {
struct work_struct unpin_work;
struct radeon_device *rdev;
int crtc_id;
u32 target_vblank;
uint64_t base;
struct drm_pending_vblank_event *event;
struct radeon_bo *old_rbo;
Expand Down
89 changes: 24 additions & 65 deletions drivers/gpu/drm/radeon/radeon_display.c
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Original file line number Diff line number Diff line change
Expand Up @@ -400,14 +400,13 @@ static void radeon_flip_work_func(struct work_struct *__work)
struct radeon_flip_work *work =
container_of(__work, struct radeon_flip_work, flip_work);
struct radeon_device *rdev = work->rdev;
struct drm_device *dev = rdev->ddev;
struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[work->crtc_id];

struct drm_crtc *crtc = &radeon_crtc->base;
unsigned long flags;
int r;
int vpos, hpos, stat, min_udelay = 0;
unsigned repcnt = 4;
struct drm_vblank_crtc *vblank = &crtc->dev->vblank[work->crtc_id];
int vpos, hpos;

down_read(&rdev->exclusive_lock);
if (work->fence) {
Expand Down Expand Up @@ -438,59 +437,25 @@ static void radeon_flip_work_func(struct work_struct *__work)
work->fence = NULL;
}

/* Wait until we're out of the vertical blank period before the one
* targeted by the flip
*/
while (radeon_crtc->enabled &&
(radeon_get_crtc_scanoutpos(dev, work->crtc_id, 0,
&vpos, &hpos, NULL, NULL,
&crtc->hwmode)
& (DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_IN_VBLANK)) ==
(DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_IN_VBLANK) &&
(int)(work->target_vblank -
dev->driver->get_vblank_counter(dev, work->crtc_id)) > 0)
usleep_range(1000, 2000);

/* We borrow the event spin lock for protecting flip_status */
spin_lock_irqsave(&crtc->dev->event_lock, flags);

/* set the proper interrupt */
radeon_irq_kms_pflip_irq_get(rdev, radeon_crtc->crtc_id);

/* If this happens to execute within the "virtually extended" vblank
* interval before the start of the real vblank interval then it needs
* to delay programming the mmio flip until the real vblank is entered.
* This prevents completing a flip too early due to the way we fudge
* our vblank counter and vblank timestamps in order to work around the
* problem that the hw fires vblank interrupts before actual start of
* vblank (when line buffer refilling is done for a frame). It
* complements the fudging logic in radeon_get_crtc_scanoutpos() for
* timestamping and radeon_get_vblank_counter_kms() for vblank counts.
*
* In practice this won't execute very often unless on very fast
* machines because the time window for this to happen is very small.
*/
while (radeon_crtc->enabled && --repcnt) {
/* GET_DISTANCE_TO_VBLANKSTART returns distance to real vblank
* start in hpos, and to the "fudged earlier" vblank start in
* vpos.
*/
stat = radeon_get_crtc_scanoutpos(rdev->ddev, work->crtc_id,
GET_DISTANCE_TO_VBLANKSTART,
&vpos, &hpos, NULL, NULL,
&crtc->hwmode);

if ((stat & (DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_ACCURATE)) !=
(DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_ACCURATE) ||
!(vpos >= 0 && hpos <= 0))
break;

/* Sleep at least until estimated real start of hw vblank */
min_udelay = (-hpos + 1) * max(vblank->linedur_ns / 1000, 5);
if (min_udelay > vblank->framedur_ns / 2000) {
/* Don't wait ridiculously long - something is wrong */
repcnt = 0;
break;
}
spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
usleep_range(min_udelay, 2 * min_udelay);
spin_lock_irqsave(&crtc->dev->event_lock, flags);
};

if (!repcnt)
DRM_DEBUG_DRIVER("Delay problem on crtc %d: min_udelay %d, "
"framedur %d, linedur %d, stat %d, vpos %d, "
"hpos %d\n", work->crtc_id, min_udelay,
vblank->framedur_ns / 1000,
vblank->linedur_ns / 1000, stat, vpos, hpos);

/* do the flip (mmio) */
radeon_page_flip(rdev, radeon_crtc->crtc_id, work->base, work->async);

Expand All @@ -499,10 +464,11 @@ static void radeon_flip_work_func(struct work_struct *__work)
up_read(&rdev->exclusive_lock);
}

static int radeon_crtc_page_flip(struct drm_crtc *crtc,
struct drm_framebuffer *fb,
struct drm_pending_vblank_event *event,
uint32_t page_flip_flags)
static int radeon_crtc_page_flip_target(struct drm_crtc *crtc,
struct drm_framebuffer *fb,
struct drm_pending_vblank_event *event,
uint32_t page_flip_flags,
uint32_t target)
{
struct drm_device *dev = crtc->dev;
struct radeon_device *rdev = dev->dev_private;
Expand Down Expand Up @@ -599,12 +565,8 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
base &= ~7;
}
work->base = base;

r = drm_crtc_vblank_get(crtc);
if (r) {
DRM_ERROR("failed to get vblank before flip\n");
goto pflip_cleanup;
}
work->target_vblank = target - drm_crtc_vblank_count(crtc) +
dev->driver->get_vblank_counter(dev, work->crtc_id);

/* We borrow the event spin lock for protecting flip_work */
spin_lock_irqsave(&crtc->dev->event_lock, flags);
Expand All @@ -613,7 +575,7 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
r = -EBUSY;
goto vblank_cleanup;
goto pflip_cleanup;
}
radeon_crtc->flip_status = RADEON_FLIP_PENDING;
radeon_crtc->flip_work = work;
Expand All @@ -626,9 +588,6 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc,
queue_work(radeon_crtc->flip_queue, &work->flip_work);
return 0;

vblank_cleanup:
drm_crtc_vblank_put(crtc);

pflip_cleanup:
if (unlikely(radeon_bo_reserve(new_rbo, false) != 0)) {
DRM_ERROR("failed to reserve new rbo in error path\n");
Expand Down Expand Up @@ -697,7 +656,7 @@ static const struct drm_crtc_funcs radeon_crtc_funcs = {
.gamma_set = radeon_crtc_gamma_set,
.set_config = radeon_crtc_set_config,
.destroy = radeon_crtc_destroy,
.page_flip = radeon_crtc_page_flip,
.page_flip_target = radeon_crtc_page_flip_target,
};

static void radeon_crtc_init(struct drm_device *dev, int index)
Expand Down

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