From 9a60d4ddb349514881ad9e6816bea50745838c6a Mon Sep 17 00:00:00 2001
From: Mario Kleiner <mario.kleiner.de@gmail.com>
Date: Fri, 6 May 2016 19:26:05 +0200
Subject: [PATCH] drm/vc4: Fix get_vblank_counter with proper no-op for Linux
4.4+
get_vblank_counter hooked up to drm_vblank_count() which alway was
non-sensical but didn't hurt in the past. Since Linux 4.4 it
triggers a WARN_ON_ONCE in drm_update_vblank_count on first vblank
irq disable, so fix it by hooking to drm_vblank_no_hw_counter().
Tested against Raspian kernel 4.4.8 tree on RPi 2B.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Fixes: b5ab5d6e3cb4 ("drm/vc4: Add KMS support for Raspberry Pi.")
---
drivers/gpu/drm/vc4/vc4_drv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 3446ece21b4ab..ef7de8eb2b633 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -91,7 +91,7 @@ static struct drm_driver vc4_drm_driver = {
.enable_vblank = vc4_enable_vblank,
.disable_vblank = vc4_disable_vblank,
- .get_vblank_counter = drm_vblank_count,
+ .get_vblank_counter = drm_vblank_no_hw_counter,
#if defined(CONFIG_DEBUG_FS)
.debugfs_init = vc4_debugfs_init,
--
2.39.5