[PATCH 2/2] Re-run BLC when gain change

[Arec Kao <arec.kao@intel.com>]

Changing the gain affects the black-level through the device;
the gain should therefore not be changed during a BLC procedure.
If the gain changes, then the BLC routine should be re-run
in some scenarios.

Signed-off-by: Arec Kao <arec.kao@intel.com>
---
 .../userspace-api/media/v4l/ext-ctrls-image-source.rst       | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
index 71f23f131f97..5ee53ba76d46 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
@@ -59,6 +59,11 @@ Image Source Control IDs
     non-sensitive.
     This control is required for automatic calibration of sensors/cameras.
 
+``V4L2_CID_BLC (integer)``
+    Changing the gain affects the black-level through the device; the gain
+    should therefore not be changed during a BLC procedure. If the gain
+    changes, the BLC routine should be re-run in some scenarios.
+
 .. c:type:: v4l2_area
 
 .. flat-table:: struct v4l2_area
-- 
2.17.1