drm/fb: drop panic handling

This really doesn't seem to have much chance of working anymore,

esp for irq context, qxl at least tries to talk to the hw,
and waits for irqs, and fails.

with runtime pm and other stuff I think we should just
bail on this for now.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_fb_helper.c

@@ -429,24 +429,6 @@ static bool drm_fb_helper_force_kernel_mode(void)
 	return error;
 }
 
-static int drm_fb_helper_panic(struct notifier_block *n, unsigned long ununsed,
-			void *panic_str)
-{
-	/*
-	 * It's a waste of time and effort to switch back to text console
-	 * if the kernel should reboot before panic messages can be seen.
-	 */
-	if (panic_timeout < 0)
-		return 0;
-
-	pr_err("panic occurred, switching back to text console\n");
-	return drm_fb_helper_force_kernel_mode();
-}
-
-static struct notifier_block paniced = {
-	.notifier_call = drm_fb_helper_panic,
-};
-
 static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
 {
 	struct drm_device *dev = fb_helper->dev;
@@ -672,9 +654,6 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
 	if (!list_empty(&fb_helper->kernel_fb_list)) {
 		list_del(&fb_helper->kernel_fb_list);
 		if (list_empty(&kernel_fb_helper_list)) {
-			pr_info("drm: unregistered panic notifier\n");
-			atomic_notifier_chain_unregister(&panic_notifier_list,
-							 &paniced);
 			unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
 		}
 	}
@@ -1109,12 +1088,7 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
 	dev_info(fb_helper->dev->dev, "fb%d: %s frame buffer device\n",
 			info->node, info->fix.id);
 
-	/* Switch back to kernel console on panic */
-	/* multi card linked list maybe */
 	if (list_empty(&kernel_fb_helper_list)) {
-		dev_info(fb_helper->dev->dev, "registered panic notifier\n");
-		atomic_notifier_chain_register(&panic_notifier_list,
-					       &paniced);
 		register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
 	}