[PATCH AUTOSEL 5.17 41/60] drm/amd/display: Check if modulo is 0 before dividing.

Sasha Levin
2022-06-07T19:13:20Z

From: David Galiffi <David.Galiffi@amd.com>

[ Upstream commit 49947b906a6bd9668eaf4f9cf691973c25c26955 ]

[How & Why]
If a value of 0 is read, then this will cause a divide-by-0 panic.

Reviewed-by: Martin Leung <Martin.Leung@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: David Galiffi <David.Galiffi@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/dce/dce_clock_source.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
index 2c7eb982eabc..054823d12403 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
@@ -1013,9 +1013,12 @@ static bool get_pixel_clk_frequency_100hz(
* not be programmed equal to DPREFCLK
*/
modulo_hz = REG_READ(MODULO[inst]);
- *pixel_clk_khz = div_u64((uint64_t)clock_hz*
- clock_source->ctx->dc->clk_mgr->dprefclk_khz*10,
- modulo_hz);
+ if (modulo_hz)
+ *pixel_clk_khz = div_u64((uint64_t)clock_hz*
+ clock_source->ctx->dc->clk_mgr->dprefclk_khz*10,
+ modulo_hz);
+ else
+ *pixel_clk_khz = 0;
} else {
/* NOTE: There is agreement with VBIOS here that MODULO is
* programmed equal to DPREFCLK, in which case PHASE will be
--
2.35.1