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 8c750d5..787c50d 100644 (file)
--- 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) {