drm/vc4: Account for interrupts in flight

Synchronously disable the IRQ to make the following cancel_work_sync invocation effective. An interrupt in flight could enqueue further overflow mem work. As we free the binner BO immediately following vc4_irq_uninstall this caused a NULL pointer dereference in the work callback vc4_overflow_mem_work. Link: #114 Signed-off-by: Stefan Schake <[email protected]> Fixes: d5b1a78 ("drm/vc4: Add support for drawing 3D frames.") Signed-off-by: Eric Anholt <[email protected]> Reviewed-by: Eric Anholt <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
anholt · Nov 14, 2017 · 253696c · 253696c
1 parent 44419ce
commit 253696c
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/drivers/gpu/drm/vc4/vc4_irq.c b/drivers/gpu/drm/vc4/vc4_irq.c
@@ -208,6 +208,9 @@ vc4_irq_postinstall(struct drm_device *dev)
 {
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 
+	/* Undo the effects of a previous vc4_irq_uninstall. */
+	enable_irq(dev->irq);
+
 	/* Enable both the render done and out of memory interrupts. */
 	V3D_WRITE(V3D_INTENA, V3D_DRIVER_IRQS);
 
@@ -225,6 +228,9 @@ vc4_irq_uninstall(struct drm_device *dev)
 	/* Clear any pending interrupts we might have left. */
 	V3D_WRITE(V3D_INTCTL, V3D_DRIVER_IRQS);
 
+	/* Finish any interrupt handler still in flight. */
+	disable_irq(dev->irq);
+
 	cancel_work_sync(&vc4->overflow_mem_work);
 }