[PATCH AUTOSEL 6.11 220/244] drm/amd/display: guard write a 0 post_divider value to HW

Sasha Levin
2024-09-25T11:52:35Z

From: "Ahmed, Muhammad" <Ahmed.Ahmed@amd.com>

[ Upstream commit 5d666496c24129edeb2bcb500498b87cc64e7f07 ]

[why]
post_divider_value should not be 0.

Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Ahmed, Muhammad <Ahmed.Ahmed@amd.com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c b/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c
index 68cd3258f4a97..a64d8f3ec93a3 100644
--- a/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c
+++ b/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c
@@ -47,7 +47,8 @@ static void dccg35_trigger_dio_fifo_resync(struct dccg *dccg)
uint32_t dispclk_rdivider_value = 0;

REG_GET(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_RDIVIDER, &dispclk_rdivider_value);
- REG_UPDATE(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_WDIVIDER, dispclk_rdivider_value);
+ if (dispclk_rdivider_value != 0)
+ REG_UPDATE(DENTIST_DISPCLK_CNTL, DENTIST_DISPCLK_WDIVIDER, dispclk_rdivider_value);
}

static void dcn35_set_dppclk_enable(struct dccg *dccg,
--
2.43.0