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authorDaniel Vetter <daniel.vetter@ffwll.ch>2012-12-01 23:43:11 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-01-20 15:29:04 +0100
commit8faf6b18a2a6bece008de1e6bb80f0c608e58483 (patch)
treee30089b80dc9706a4842c9d53094a4f9ecadb2e4 /include/drm
parent7d1f9aeff1ee4a20b1aeb377dd0f579fe9647619 (diff)
drm: review locking rules in drm_crtc.c
- config_cleanup was confused: It claimed that callers need to hold the modeset lock, but the connector|encoder_cleanup helpers grabbed that themselves (note that crtc_cleanup did _not_ grab the modeset lock). Which resulted in all drivers _not_ hodling the lock. Since this is for single-threaded cleanup code, drop the requirement from docs and also drop the lock_grabbing from all _cleanup functions. - Kill the LOCKING section in the doctype, since clearly we're not good enough to keep them up-to-date. And misleading locking documentation is worse than useless (see e.g. the comment in the vmgfx driver about the cleanup mess). And since for most functions the very first line either grabs the lock or has a WARN_ON(!locked) the documentation doesn't really add anything. - Instead put in some effort into explaining the only two special cases a bit better: config_init and config_cleanup are both called from single-threaded setup/teardown code, so don't do any locking. It's the driver's job though to enforce this. - Where lacking, add a WARN_ON(!is_locked). Not many places though, since locking around fbdev setup/teardown is through-roughly screwed up, and so will break almost every single WARN annotation I've tried to add. - Add a drm_modeset_is_locked helper - the Grate Modset Locking Rework will use the compiler to assist in the big reorg by renaming the mode lock, so start encapsulating things. Unfortunately this ended up in the "wrong" header file since it needs the definition of struct drm_device. v2: Drop most WARNS again - we hit them all over the place, mostly in the setup and teardown sequences. And trying to fix it up leads to nice deadlocks, since the locking in the setup code is really inconsistent. Reviewed-by: Rob Clark <rob@ti.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/drmP.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index fad21c927a38..3c609abe8c80 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1276,6 +1276,11 @@ static inline int drm_device_is_unplugged(struct drm_device *dev)
return ret;
}
+static inline bool drm_modeset_is_locked(struct drm_device *dev)
+{
+ return mutex_is_locked(&dev->mode_config.mutex);
+}
+
/******************************************************************/
/** \name Internal function definitions */
/*@{*/