[PATCH 5.2 066/144] drm/amd/display: Wait for backlight programming completion in set backlight level

From: Greg Kroah-Hartman
Date: Wed Aug 14 2019 - 13:04:48 EST


[ Upstream commit c7990daebe71d11a9e360b5c3b0ecd1846a3a4bb ]

[WHY]
Currently we don't wait for blacklight programming completion in DMCU
when setting backlight level. Some sequences such as PSR static screen
event trigger reprogramming requires it to be complete.

[How]
Add generic wait for dmcu command completion in set backlight level.

Signed-off-by: SivapiriyanKumarasamy <sivapiriyan.kumarasamy@xxxxxxx>
Reviewed-by: Anthony Koo <Anthony.Koo@xxxxxxx>
Acked-by: Leo Li <sunpeng.li@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
index 2959c3c9390b9..da30ae04e82bb 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
@@ -234,6 +234,10 @@ static void dmcu_set_backlight_level(
s2 |= (backlight_8_bit << ATOM_S2_CURRENT_BL_LEVEL_SHIFT);

REG_WRITE(BIOS_SCRATCH_2, s2);
+
+ /* waitDMCUReadyForCmd */
+ REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT,
+ 0, 1, 80000);
}

static void dce_abm_init(struct abm *abm)
--
2.20.1