[PATCH 5.4 133/434] drm/amd/display: Properly round nominal frequency for SPD

Greg Kroah-Hartman
2019-12-29T18:08:49Z

From: Aric Cyr <aric.cyr@amd.com>

[ Upstream commit c59802313e84bede954235b3a5dd0dd5325f49c5 ]

[Why]
Some displays rely on the SPD verticle frequency maximum value.
Must round the calculated refresh rate to the nearest integer.

[How]
Round the nominal calculated refresh rate to the nearest whole
integer.

Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../gpu/drm/amd/display/modules/freesync/freesync.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
index ec70c9b12e1a..0978c698f0f8 100644
--- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
+++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
@@ -743,6 +743,10 @@ void mod_freesync_build_vrr_params(struct mod_freesync *mod_freesync,
nominal_field_rate_in_uhz =
mod_freesync_calc_nominal_field_rate(stream);

+ /* Rounded to the nearest Hz */
+ nominal_field_rate_in_uhz = 1000000ULL *
+ div_u64(nominal_field_rate_in_uhz + 500000, 1000000);
+
min_refresh_in_uhz = in_config->min_refresh_in_uhz;
max_refresh_in_uhz = in_config->max_refresh_in_uhz;

@@ -996,14 +1000,13 @@ unsigned long long mod_freesync_calc_nominal_field_rate(
const struct dc_stream_state *stream)
{
unsigned long long nominal_field_rate_in_uhz = 0;
+ unsigned int total = stream->timing.h_total * stream->timing.v_total;

- /* Calculate nominal field rate for stream */
+ /* Calculate nominal field rate for stream, rounded up to nearest integer */
nominal_field_rate_in_uhz = stream->timing.pix_clk_100hz / 10;
nominal_field_rate_in_uhz *= 1000ULL * 1000ULL * 1000ULL;
- nominal_field_rate_in_uhz = div_u64(nominal_field_rate_in_uhz,
- stream->timing.h_total);
- nominal_field_rate_in_uhz = div_u64(nominal_field_rate_in_uhz,
- stream->timing.v_total);
+
+ nominal_field_rate_in_uhz = div_u64(nominal_field_rate_in_uhz, total);

return nominal_field_rate_in_uhz;
}
--
2.20.1