Commit a3a88587 authored by George Shen's avatar George Shen Committed by Alex Deucher

drm/amd/display: Fix divide-by-zero in DPPCLK and DISPCLK calculation

[Why]
Certain use cases will pass in zero in the new_clocks parameter for all
clocks. This results in a divide-by-zero error when attempting to round
up the new clock.

When new_clocks are zero, no rounding is required, so we can skip it.

[How]
Guard the division calculation with a check to make sure clocks are not
zero.
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Acked-by: default avatarRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: default avatarGeorge Shen <george.shen@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 04e6931a
......@@ -335,14 +335,16 @@ static void dcn32_update_dppclk_dispclk_freq(struct clk_mgr_internal *clk_mgr, s
int dpp_divider = 0;
int disp_divider = 0;
dpp_divider = DENTIST_DIVIDER_RANGE_SCALE_FACTOR
* clk_mgr->base.dentist_vco_freq_khz / new_clocks->dppclk_khz;
disp_divider = DENTIST_DIVIDER_RANGE_SCALE_FACTOR
* clk_mgr->base.dentist_vco_freq_khz / new_clocks->dispclk_khz;
// Divide back the previous result to round up to the actual clock value that will be set from divider
new_clocks->dppclk_khz = (DENTIST_DIVIDER_RANGE_SCALE_FACTOR * clk_mgr->base.dentist_vco_freq_khz) / dpp_divider;
new_clocks->dispclk_khz = (DENTIST_DIVIDER_RANGE_SCALE_FACTOR * clk_mgr->base.dentist_vco_freq_khz) / disp_divider;
if (new_clocks->dppclk_khz) {
dpp_divider = DENTIST_DIVIDER_RANGE_SCALE_FACTOR
* clk_mgr->base.dentist_vco_freq_khz / new_clocks->dppclk_khz;
new_clocks->dppclk_khz = (DENTIST_DIVIDER_RANGE_SCALE_FACTOR * clk_mgr->base.dentist_vco_freq_khz) / dpp_divider;
}
if (new_clocks->dispclk_khz > 0) {
disp_divider = DENTIST_DIVIDER_RANGE_SCALE_FACTOR
* clk_mgr->base.dentist_vco_freq_khz / new_clocks->dispclk_khz;
new_clocks->dispclk_khz = (DENTIST_DIVIDER_RANGE_SCALE_FACTOR * clk_mgr->base.dentist_vco_freq_khz) / disp_divider;
}
}
static void dcn32_update_clocks(struct clk_mgr *clk_mgr_base,
......
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