drm: add some comments to drm_wait_vblank and drm_queue_vblank_event

[pandora-kernel.git] / drivers / gpu / drm / drm_irq.c

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 2022a5c..aa3ac01 100644 (file)
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -40,6 +40,7 @@
 #include <linux/slab.h>
 
 #include <linux/vgaarb.h>
+#include <linux/export.h>
 
 /* Access macro for slots in vblank timestamp ringbuffer. */
 #define vblanktimestamp(dev, crtc, count) ( \
@@ -291,11 +292,14 @@ static void drm_irq_vgaarb_nokms(void *cookie, bool state)
        if (!dev->irq_enabled)
                return;
 
-       if (state)
-               dev->driver->irq_uninstall(dev);
-       else {
-               dev->driver->irq_preinstall(dev);
-               dev->driver->irq_postinstall(dev);
+       if (state) {
+               if (dev->driver->irq_uninstall)
+                       dev->driver->irq_uninstall(dev);
+       } else {
+               if (dev->driver->irq_preinstall)
+                       dev->driver->irq_preinstall(dev);
+               if (dev->driver->irq_postinstall)
+                       dev->driver->irq_postinstall(dev);
        }
 }
 
@@ -338,7 +342,8 @@ int drm_irq_install(struct drm_device *dev)
        DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
 
        /* Before installing handler */
-       dev->driver->irq_preinstall(dev);
+       if (dev->driver->irq_preinstall)
+               dev->driver->irq_preinstall(dev);
 
        /* Install handler */
        if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
@@ -363,11 +368,16 @@ int drm_irq_install(struct drm_device *dev)
                vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
 
        /* After installing handler */
-       ret = dev->driver->irq_postinstall(dev);
+       if (dev->driver->irq_postinstall)
+               ret = dev->driver->irq_postinstall(dev);
+
        if (ret < 0) {
                mutex_lock(&dev->struct_mutex);
                dev->irq_enabled = 0;
                mutex_unlock(&dev->struct_mutex);
+               if (!drm_core_check_feature(dev, DRIVER_MODESET))
+                       vga_client_register(dev->pdev, NULL, NULL, NULL);
+               free_irq(drm_dev_to_irq(dev), dev);
        }
 
        return ret;
@@ -413,7 +423,8 @@ int drm_irq_uninstall(struct drm_device *dev)
        if (!drm_core_check_feature(dev, DRIVER_MODESET))
                vga_client_register(dev->pdev, NULL, NULL, NULL);
 
-       dev->driver->irq_uninstall(dev);
+       if (dev->driver->irq_uninstall)
+               dev->driver->irq_uninstall(dev);
 
        free_irq(drm_dev_to_irq(dev), dev);
 
@@ -1114,6 +1125,7 @@ static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
                trace_drm_vblank_event_delivered(current->pid, pipe,
                                                 vblwait->request.sequence);
        } else {
+               /* drm_handle_vblank_events will call drm_vblank_put */
                list_add_tail(&e->base.link, &dev->vblank_event_list);
                vblwait->reply.sequence = vblwait->request.sequence;
        }
@@ -1194,8 +1206,12 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
                goto done;
        }
 
-       if (flags & _DRM_VBLANK_EVENT)
+       if (flags & _DRM_VBLANK_EVENT) {
+               /* must hold on to the vblank ref until the event fires
+                * drm_vblank_put will be called asynchronously
+                */
                return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
+       }
 
        if ((flags & _DRM_VBLANK_NEXTONMISS) &&
            (seq - vblwait->request.sequence) <= (1<<23)) {