[PATCH AUTOSEL 5.1 027/141] drm/amd/display: Increase Backlight Gain Step Size

[Sasha Levin]

From: Eryk Brol <eryk.brol at amd.com>

[ Upstream commit e25228b02e4833e5b0fdd262801a2ae6cc72b39d ]

[Why]
Some backlight tests fail due to backlight settling
taking too long. This happens because the step
size used to change backlight levels is too small.

[How]
1. Change the size of the backlight gain step size
2. Change how DMCU firmware gets the step size value
   so that it is passed in by driver during DMCU initn

Signed-off-by: Eryk Brol <eryk.brol at amd.com>
Reviewed-by: Jun Lei <Jun.Lei at amd.com>
Acked-by: Leo Li <sunpeng.li at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c | 3 +++
 drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.h | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
index c2926cf19dee..407fb22be66a 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
@@ -365,6 +365,9 @@ static bool dcn10_dmcu_init(struct dmcu *dmcu)
 		/* Set initialized ramping boundary value */
 		REG_WRITE(MASTER_COMM_DATA_REG1, 0xFFFF);
 
+		/* Set backlight ramping stepsize */
+		REG_WRITE(MASTER_COMM_DATA_REG2, abm_gain_stepsize);
+
 		/* Set command to initialize microcontroller */
 		REG_UPDATE(MASTER_COMM_CMD_REG, MASTER_COMM_CMD_REG_BYTE0,
 			MCP_INIT_DMCU);
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.h b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.h
index c24c0e5ea44e..249a3c23b607 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.h
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.h
@@ -263,4 +263,6 @@ struct dmcu *dcn10_dmcu_create(
 
 void dce_dmcu_destroy(struct dmcu **dmcu);
 
+static const uint32_t abm_gain_stepsize = 0x0060;
+
 #endif /* _DCE_ABM_H_ */
-- 
2.20.1