linux-kernel - [PATCH v2 2/2] drm: bridge: document bridge attach/detach imbalance

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Message-Id: <20180806061910.29914-3-peda@axentia.se>
Date:   Mon,  6 Aug 2018 08:19:10 +0200
From:   Peter Rosin <peda@...ntia.se>
To:     linux-kernel@...r.kernel.org
Cc:     Peter Rosin <peda@...ntia.se>,
        Gustavo Padovan <gustavo@...ovan.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Sean Paul <seanpaul@...omium.org>,
        David Airlie <airlied@...ux.ie>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Vincent Abriou <vincent.abriou@...com>,
        dri-devel@...ts.freedesktop.org, Daniel Vetter <daniel@...ll.ch>
Subject: [PATCH v2 2/2] drm: bridge: document bridge attach/detach imbalance

Since 4a878c03d562 ("drm: bridge: Detach bridge from encoder at encoder
cleanup time"), it is generally no longer correct to detach bridges from
encoders manually. Document that.

Signed-off-by: Peter Rosin <peda@...ntia.se>
---
 drivers/gpu/drm/drm_bridge.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 1638bfe9627c..ba7025041e46 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -104,6 +104,10 @@ EXPORT_SYMBOL(drm_bridge_remove);
  * If non-NULL the previous bridge must be already attached by a call to this
  * function.
  *
+ * Note that bridges attached to encoders are auto-detached during encoder
+ * cleanup in drm_encoder_cleanup(), so drm_bridge_attach() should generally
+ * *not* be balanced with a drm_bridge_detach() in driver code.
+ *
  * RETURNS:
  * Zero on success, error code on failure
  */
-- 
2.11.0