1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/gpu/drm/armada/armada_crtc.c b/drivers/gpu/drm/armada/armada_crtc.c
index 03eeee11dd5b..42a40daff132 100644
--- a/drivers/gpu/drm/armada/armada_crtc.c
+++ b/drivers/gpu/drm/armada/armada_crtc.c
@@ -519,8 +519,9 @@ static irqreturn_t armada_drm_irq(int irq, void *arg)
         u32 v, stat = readl_relaxed(dcrtc->base + LCD_SPU_IRQ_ISR);
 
         /*
-         * This is rediculous - rather than writing bits to clear, we
-         * have to set the actual status register value.  This is racy.
+         * Reading the ISR appears to clear bits provided CLEAN_SPU_IRQ_ISR
+         * is set.  Writing has some other effect to acknowledge the IRQ -
+         * without this, we only get a single IRQ.
          */
         writel_relaxed(0, dcrtc->base + LCD_SPU_IRQ_ISR);
 
@@ -1116,16 +1117,22 @@ armada_drm_crtc_set_property(struct drm_crtc *crtc,
 static int armada_drm_crtc_enable_vblank(struct drm_crtc *crtc)
 {
         struct armada_crtc *dcrtc = drm_to_armada_crtc(crtc);
+        unsigned long flags;
 
+        spin_lock_irqsave(&dcrtc->irq_lock, flags);
         armada_drm_crtc_enable_irq(dcrtc, VSYNC_IRQ_ENA);
+        spin_unlock_irqrestore(&dcrtc->irq_lock, flags);
         return 0;
 }
 
 static void armada_drm_crtc_disable_vblank(struct drm_crtc *crtc)
 {
         struct armada_crtc *dcrtc = drm_to_armada_crtc(crtc);
+        unsigned long flags;
 
+        spin_lock_irqsave(&dcrtc->irq_lock, flags);
         armada_drm_crtc_disable_irq(dcrtc, VSYNC_IRQ_ENA);
+        spin_unlock_irqrestore(&dcrtc->irq_lock, flags);
 }
 
 static const struct drm_crtc_funcs armada_crtc_funcs = {
@@ -1415,6 +1422,7 @@ static int armada_drm_crtc_create(struct drm_device *drm, struct device *dev,
                        CFG_PDWN64x66, dcrtc->base + LCD_SPU_SRAM_PARA1);
         writel_relaxed(0x2032ff81, dcrtc->base + LCD_SPU_DMA_CTRL1);
         writel_relaxed(dcrtc->irq_ena, dcrtc->base + LCD_SPU_IRQ_ENA);
+        readl_relaxed(dcrtc->base + LCD_SPU_IRQ_ISR);
         writel_relaxed(0, dcrtc->base + LCD_SPU_IRQ_ISR);
 
         ret = devm_request_irq(dev, irq, armada_drm_irq, 0, "armada_drm_crtc",