drm/tilcdc: Do not update the next frame buffer close to vertical blank
Do not update the next frame buffer close to vertical blank. This is
to avoid situation when the frame changes between writing of
LCDC_DMA_FB_BASE_ADDR_0_REG and LCDC_DMA_FB_CEILING_ADDR_0_REG.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
[Added description to the patch]
Signed-off-by: Jyri Sarha <jsarha@ti.com>
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 3257228..b1df046 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -21,6 +21,8 @@
#include "tilcdc_drv.h"
#include "tilcdc_regs.h"
+#define TILCDC_VBLANK_SAFETY_THRESHOLD_US 1000
+
struct tilcdc_crtc {
struct drm_crtc base;
@@ -29,8 +31,12 @@
int dpms;
wait_queue_head_t frame_done_wq;
bool frame_done;
+ spinlock_t irq_lock;
+
+ ktime_t last_vblank;
struct drm_framebuffer *curr_fb;
+ struct drm_framebuffer *next_fb;
/* for deferred fb unref's: */
struct drm_flip_work unref_work;
@@ -146,6 +152,8 @@
struct drm_device *dev = crtc->dev;
int r;
unsigned long flags;
+ s64 tdiff;
+ ktime_t next_vblank;
r = tilcdc_verify_fb(crtc, fb);
if (r)
@@ -162,12 +170,21 @@
pm_runtime_get_sync(dev->dev);
+ spin_lock_irqsave(&tilcdc_crtc->irq_lock, flags);
- set_scanout(crtc, fb);
+ next_vblank = ktime_add_us(tilcdc_crtc->last_vblank,
+ 1000000 / crtc->hwmode.vrefresh);
- spin_lock_irqsave(&dev->event_lock, flags);
+ tdiff = ktime_to_us(ktime_sub(next_vblank, ktime_get()));
+
+ if (tdiff >= TILCDC_VBLANK_SAFETY_THRESHOLD_US)
+ set_scanout(crtc, fb);
+ else
+ tilcdc_crtc->next_fb = fb;
+
tilcdc_crtc->event = event;
- spin_unlock_irqrestore(&dev->event_lock, flags);
+
+ spin_unlock_irqrestore(&tilcdc_crtc->irq_lock, flags);
pm_runtime_put_sync(dev->dev);
@@ -211,6 +228,12 @@
pm_runtime_put_sync(dev->dev);
+ if (tilcdc_crtc->next_fb) {
+ drm_flip_work_queue(&tilcdc_crtc->unref_work,
+ tilcdc_crtc->next_fb);
+ tilcdc_crtc->next_fb = NULL;
+ }
+
if (tilcdc_crtc->curr_fb) {
drm_flip_work_queue(&tilcdc_crtc->unref_work,
tilcdc_crtc->curr_fb);
@@ -651,19 +674,39 @@
if (stat & LCDC_END_OF_FRAME0) {
unsigned long flags;
+ bool skip_event = false;
+ ktime_t now;
+
+ now = ktime_get();
drm_flip_work_commit(&tilcdc_crtc->unref_work, priv->wq);
- drm_handle_vblank(dev, 0);
+ spin_lock_irqsave(&tilcdc_crtc->irq_lock, flags);
- spin_lock_irqsave(&dev->event_lock, flags);
+ tilcdc_crtc->last_vblank = now;
- if (tilcdc_crtc->event) {
- drm_send_vblank_event(dev, 0, tilcdc_crtc->event);
- tilcdc_crtc->event = NULL;
+ if (tilcdc_crtc->next_fb) {
+ set_scanout(crtc, tilcdc_crtc->next_fb);
+ tilcdc_crtc->next_fb = NULL;
+ skip_event = true;
}
- spin_unlock_irqrestore(&dev->event_lock, flags);
+ spin_unlock_irqrestore(&tilcdc_crtc->irq_lock, flags);
+
+ drm_handle_vblank(dev, 0);
+
+ if (!skip_event) {
+ struct drm_pending_vblank_event *event;
+
+ spin_lock_irqsave(&dev->event_lock, flags);
+
+ event = tilcdc_crtc->event;
+ tilcdc_crtc->event = NULL;
+ if (event)
+ drm_send_vblank_event(dev, 0, event);
+
+ spin_unlock_irqrestore(&dev->event_lock, flags);
+ }
}
if (priv->rev == 2) {
@@ -697,6 +740,8 @@
drm_flip_work_init(&tilcdc_crtc->unref_work,
"unref", unref_worker);
+ spin_lock_init(&tilcdc_crtc->irq_lock);
+
ret = drm_crtc_init(dev, crtc, &tilcdc_crtc_funcs);
if (ret < 0)
goto fail;