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drm/vc4: dsi: Remove entry to ULPS from vc4_dsi post_disable
authorDave Stevenson <dave.stevenson@raspberrypi.com>
Wed, 7 Dec 2022 10:22:49 +0000 (11:22 +0100)
committerMaxime Ripard <maxime@cerno.tech>
Thu, 15 Dec 2022 07:57:17 +0000 (08:57 +0100)
commit7d7bf35d630751fb27f2041c680a5ddccae9d83c
tree4fca951626fd3f6788b8cba91d4da0eb0b071679
parent78df640394cd0de88b9f84982f90f2079e60a5b7
drm/vc4: dsi: Remove entry to ULPS from vc4_dsi post_disable

Post_disable was sending the D-PHY sequence to put any device
into ULPS suspend mode, and then cutting power to the DSI block.
The power-on reset state of the DSI block is for DSI to be in
an operational state, not ULPS, so it then never sent the sequence
for exiting ULPS. Any attached device that didn't have an external
reset therefore remained in ULPS / standby, and didn't function.

Use of ULPS isn't well specified in DRM, therefore remove entering
it to avoid the above situation.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20221207-rpi-dsi-bridge-v1-6-8f68ee0b0adb@cerno.tech
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
drivers/gpu/drm/vc4/vc4_dsi.c