From b0b5ae1ea6701cf9395f3132d559a5379a4fb73e Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Fri, 11 Feb 2022 14:15:26 +0000
Subject: [PATCH] drm/vc4: 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>
---
 drivers/gpu/drm/vc4/vc4_dsi.c | 2 --
 1 file changed, 2 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_dsi.c
+++ b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -813,8 +813,6 @@ static void vc4_dsi_bridge_post_disable(
 	struct vc4_dsi *dsi = bridge_to_vc4_dsi(bridge);
 	struct device *dev = &dsi->pdev->dev;
 
-	vc4_dsi_ulps(dsi, true);
-
 	clk_disable_unprepare(dsi->pll_phy_clock);
 	clk_disable_unprepare(dsi->escape_clock);
 	clk_disable_unprepare(dsi->pixel_clock);
