From: Michel Dänzer <michel.daen...@amd.com>

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.

Signed-off-by: Michel Dänzer <michel.daen...@amd.com>
---
 drivers/gpu/drm/radeon/radeon.h         |  1 +
 drivers/gpu/drm/radeon/radeon_display.c | 89 +++++++++------------------------
 2 files changed, 25 insertions(+), 65 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 5633ee3..1b0dcad 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -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;
diff --git a/drivers/gpu/drm/radeon/radeon_display.c 
b/drivers/gpu/drm/radeon/radeon_display.c
index 5f1cd69..bd9d995 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -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) {
@@ -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);
 
@@ -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;
@@ -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);
@@ -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;
@@ -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");
@@ -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)
-- 
2.8.1

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