drm: fix irq naming for kms drivers.

allocating devname in the i915 driver was a hack originally and I
forgot to figure out how to do this properly back then.

So this is the cleaner version that just picks devname or driver name
in the irq code.

It removes the devname allocs from the i915 driver.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_irq.c

@@ -196,6 +196,7 @@ int drm_irq_install(struct drm_device *dev)
 {
 	int ret = 0;
 	unsigned long sh_flags = 0;
+	char *irqname;
 
 	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 		return -EINVAL;
@@ -227,8 +228,13 @@ int drm_irq_install(struct drm_device *dev)
 	if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
 		sh_flags = IRQF_SHARED;
 
+	if (dev->devname)
+		irqname = dev->devname;
+	else
+		irqname = dev->driver->name;
+
 	ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
-			  sh_flags, dev->devname, dev);
+			  sh_flags, irqname, dev);
 
 	if (ret < 0) {
 		mutex_lock(&dev->struct_mutex);

drivers/gpu/drm/i915/i915_dma.c

@@ -987,12 +987,6 @@ static int i915_load_modeset_init(struct drm_device *dev)
 	int fb_bar = IS_I9XX(dev) ? 2 : 0;
 	int ret = 0;
 
-	dev->devname = kstrdup(DRIVER_NAME, GFP_KERNEL);
-	if (!dev->devname) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
 	dev->mode_config.fb_base = drm_get_resource_start(dev, fb_bar) &
 		0xff000000;
 
@@ -1006,7 +1000,7 @@ static int i915_load_modeset_init(struct drm_device *dev)
 
 	ret = i915_probe_agp(dev, &agp_size, &prealloc_size);
 	if (ret)
-		goto kfree_devname;
+		goto out;
 
 	/* Basic memrange allocator for stolen space (aka vram) */
 	drm_mm_init(&dev_priv->vram, 0, prealloc_size);
@@ -1024,7 +1018,7 @@ static int i915_load_modeset_init(struct drm_device *dev)
 
 	ret = i915_gem_init_ringbuffer(dev);
 	if (ret)
-		goto kfree_devname;
+		goto out;
 
 	/* Allow hardware batchbuffers unless told otherwise.
 	 */
@@ -1056,8 +1050,6 @@ static int i915_load_modeset_init(struct drm_device *dev)
 
 destroy_ringbuffer:
 	i915_gem_cleanup_ringbuffer(dev);
-kfree_devname:
-	kfree(dev->devname);
 out:
 	return ret;
 }