drm/dp/mst: Sideband message transaction to power up/down nodes
authorDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Thu, 7 Sep 2017 00:14:58 +0000 (17:14 -0700)
committerVille Syrjälä <ville.syrjala@linux.intel.com>
Mon, 11 Sep 2017 13:03:57 +0000 (16:03 +0300)
commit0bb9c2b27f5e503e683ad27a0f0a6286f5b5da34
tree13a0cb3d28a6c0d135fbe52273768c26838b787c
parent8a50b9bd5679d5788f2f7add576fbd8e3ad6fed6
drm/dp/mst: Sideband message transaction to power up/down nodes

The POWER_DOWN_PHY and POWER_UP_PHY sideband message transactions allow
the source to reqest any node in a mst path or a whole path to be
powered down or up. This allows drivers to target a specific sink in the
MST topology, an improvement over just power managing the imediate
downstream device. Secondly, since the request-reply protocol waits for an
ACK, we can be sure that a downstream sink has enough time to respond to a
power up/down request.

v2: Fix memory leak (Lyude)
Cc: Lyude <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170907001458.9399-1-dhinakaran.pandiyan@intel.com
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
drivers/gpu/drm/drm_dp_mst_topology.c
include/drm/drm_dp_mst_helper.h