drm/msm/mdp4: cure for the cursor blues (v2)

The hw cursor is relatively adept at triggering underflows, which
manifest as a "blue flash" (since blue is configured as the underflow
color).  Juggle a few things around to tighten up the timing for setting
cursor registers in DONE irq.

And most importantly, don't ever disable the hw cursor.  Instead flip it
to a blank/empty cursor.  This seems far more reliable, as even simply
clearing the cursor-enable bit (with no other updates in previous/
following frames) can in some cases cause underflow.

v1: original
v2: add missing locking spotted by Micah

Cc: Micah Richert <richert@braincorporation.com>
Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
index 3e6c0f3..ef9957d 100644 (file)
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
@@ -510,9 +510,8 @@ static void update_cursor(struct drm_crtc *crtc)
                                        MDP4_DMA_CURSOR_BLEND_CONFIG_CURSOR_EN);
                } else {
                        /* disable cursor: */
-                       mdp4_write(mdp4_kms, REG_MDP4_DMA_CURSOR_BASE(dma), 0);
-                       mdp4_write(mdp4_kms, REG_MDP4_DMA_CURSOR_BLEND_CONFIG(dma),
-                                       MDP4_DMA_CURSOR_BLEND_CONFIG_FORMAT(CURSOR_ARGB));
+                       mdp4_write(mdp4_kms, REG_MDP4_DMA_CURSOR_BASE(dma),
+                                       mdp4_kms->blank_cursor_iova);
                }
 
                /* and drop the iova ref + obj rev when done scanning out: */
@@ -574,11 +573,9 @@ static int mdp4_crtc_cursor_set(struct drm_crtc *crtc,
 
        if (old_bo) {
                /* drop our previous reference: */
-               msm_gem_put_iova(old_bo, mdp4_kms->id);
-               drm_gem_object_unreference_unlocked(old_bo);
+               drm_flip_work_queue(&mdp4_crtc->unref_cursor_work, old_bo);
        }
 
-       crtc_flush(crtc);
        request_pending(crtc, PENDING_CURSOR);
 
        return 0;

diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_irq.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_irq.c
index c740ccd..8edd531 100644 (file)
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_irq.c
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_irq.c
@@ -70,12 +70,12 @@ irqreturn_t mdp4_irq(struct msm_kms *kms)
 
        VERB("status=%08x", status);
 
+       mdp_dispatch_irqs(mdp_kms, status);
+
        for (id = 0; id < priv->num_crtcs; id++)
                if (status & mdp4_crtc_vblank(priv->crtcs[id]))
                        drm_handle_vblank(dev, id);
 
-       mdp_dispatch_irqs(mdp_kms, status);
-
        return IRQ_HANDLED;
 }
 

diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
index 272e707..0bb4faa 100644 (file)
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c
@@ -144,6 +144,10 @@ static void mdp4_preclose(struct msm_kms *kms, struct drm_file *file)
 static void mdp4_destroy(struct msm_kms *kms)
 {
        struct mdp4_kms *mdp4_kms = to_mdp4_kms(to_mdp_kms(kms));
+       if (mdp4_kms->blank_cursor_iova)
+               msm_gem_put_iova(mdp4_kms->blank_cursor_bo, mdp4_kms->id);
+       if (mdp4_kms->blank_cursor_bo)
+               drm_gem_object_unreference(mdp4_kms->blank_cursor_bo);
        kfree(mdp4_kms);
 }
 
@@ -372,6 +376,23 @@ struct msm_kms *mdp4_kms_init(struct drm_device *dev)
                goto fail;
        }
 
+       mutex_lock(&dev->struct_mutex);
+       mdp4_kms->blank_cursor_bo = msm_gem_new(dev, SZ_16K, MSM_BO_WC);
+       mutex_unlock(&dev->struct_mutex);
+       if (IS_ERR(mdp4_kms->blank_cursor_bo)) {
+               ret = PTR_ERR(mdp4_kms->blank_cursor_bo);
+               dev_err(dev->dev, "could not allocate blank-cursor bo: %d\n", ret);
+               mdp4_kms->blank_cursor_bo = NULL;
+               goto fail;
+       }
+
+       ret = msm_gem_get_iova(mdp4_kms->blank_cursor_bo, mdp4_kms->id,
+                       &mdp4_kms->blank_cursor_iova);
+       if (ret) {
+               dev_err(dev->dev, "could not pin blank-cursor bo: %d\n", ret);
+               goto fail;
+       }
+
        return kms;
 
 fail:

diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h
index 66a4d31..715520c 100644 (file)
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h
@@ -44,6 +44,10 @@ struct mdp4_kms {
        struct clk *lut_clk;
 
        struct mdp_irq error_handler;
+
+       /* empty/blank cursor bo to use when cursor is "disabled" */
+       struct drm_gem_object *blank_cursor_bo;
+       uint32_t blank_cursor_iova;
 };
 #define to_mdp4_kms(x) container_of(x, struct mdp4_kms, base)
 

diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c
index 353d494..f2b985b 100644 (file)
--- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c
+++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_irq.c
@@ -71,11 +71,11 @@ static void mdp5_irq_mdp(struct mdp_kms *mdp_kms)
 
        VERB("status=%08x", status);
 
+       mdp_dispatch_irqs(mdp_kms, status);
+
        for (id = 0; id < priv->num_crtcs; id++)
                if (status & mdp5_crtc_vblank(priv->crtcs[id]))
                        drm_handle_vblank(dev, id);
-
-       mdp_dispatch_irqs(mdp_kms, status);
 }
 
 irqreturn_t mdp5_irq(struct msm_kms *kms)