From 732d50b431dca2f3f78fc21ba9b7ed9d06bb01ce Mon Sep 17 00:00:00 2001 From: Alex Deucher Date: Mon, 7 Apr 2014 10:33:45 -0400 Subject: drm/dp/i2c: Update comments about common i2c over dp assumptions (v3) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If you are using the common dp over i2c functionality, it is asumed that the aux transfer function does not modify the any of the msg structure other than the reply field. Doing so breaks the logic in the common code. v2: update struct drm_dp_aux comments about assumptions v3 (chk): rebased on upstream changes Signed-off-by: Alex Deucher Cc: Ville Syrjälä Cc: Jani Nikula Cc: Thierry Reding Reviewed-by: Ville Syrjälä Signed-off-by: Christian König --- include/drm/drm_dp_helper.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/drm') diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index b4f58914bf7..cfcacec5b89 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -456,6 +456,10 @@ struct drm_dp_aux_msg { * transactions. The drm_dp_aux_register_i2c_bus() function registers an * I2C adapter that can be passed to drm_probe_ddc(). Upon removal, drivers * should call drm_dp_aux_unregister_i2c_bus() to remove the I2C adapter. + * + * Note that the aux helper code assumes that the .transfer() function + * only modifies the reply field of the drm_dp_aux_msg structure. The + * retry logic and i2c helpers assume this is the case. */ struct drm_dp_aux { const char *name; -- cgit v1.2.3-18-g5258