drm/radeon: Provide page_flip_target hook

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>

2 files changed, 25 insertions, 65 deletions

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 5633ee3eb46e..1b0dcad916b0 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 c3206fb8f4cf..890171f08987 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)