drm: Add NULL check about irq functions

The struct drm_driver has some function pointers for irq. They are
gpu specific and some functions aren't essential things. This can
prevents creation of unnecessary dummy function for irq.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 15 insertions, 8 deletions

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 9be574fbcc2f..3830e9e478c0 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -291,11 +291,14 @@ 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 +341,8 @@ 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))
@@ -363,7 +367,9 @@ 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;
@@ -416,7 +422,8 @@ 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);