From: Damien Lespiau <damien.lespiau@intel.com>
Date: Tue, 15 Oct 2013 17:55:32 +0000 (+0100)
Subject: drm/i915: Enforce going back to none before changing CRC source
X-Git-Tag: next-20131017~56^2~22
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ae676fcd2a93bf1809cddbd79e37b37609791dc2;p=karo-tx-linux.git

drm/i915: Enforce going back to none before changing CRC source

This way we can have some init/fini code on those transitions.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 8c750d5110a1..787c50d194d4 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1816,6 +1816,10 @@ static int pipe_crc_set_source(struct drm_device *dev, enum pipe pipe,
 	if (pipe_crc->source == source)
 		return 0;
 
+	/* forbid changing the source without going back to 'none' */
+	if (pipe_crc->source && source)
+		return -EINVAL;
+
 	pipe_crc->source = source;
 
 	switch (source) {