[PATCH 06/11] drm/amd/display: Added case for when RR equals panel's max RR using freesync

[Ray Wu]

From: Harold Sun <Harold.Sun at amd.com>

[WHY]
Rounding error sometimes occurs when the refresh rate is equal to a panel's
max refresh rate, causing HDMI compliance failures.

[HOW]
Added a case so that we round up to avoid v_total_min to be below a panel's
minimum bound.

Reviewed-by: Jun Lei <jun.lei at amd.com>
Signed-off-by: Harold Sun <Harold.Sun at amd.com>
Signed-off-by: Ray Wu <ray.wu at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc_hw_types.h            | 1 +
 drivers/gpu/drm/amd/display/modules/freesync/freesync.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_hw_types.h b/drivers/gpu/drm/amd/display/dc/dc_hw_types.h
index 809fc696962d..667852517246 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_hw_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_hw_types.h
@@ -974,6 +974,7 @@ struct dc_crtc_timing {
 	uint32_t pix_clk_100hz;
 
 	uint32_t min_refresh_in_uhz;
+	uint32_t max_refresh_in_uhz;
 
 	uint32_t vic;
 	uint32_t hdmi_vic;
diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
index 6a939f2f2fb9..71efd2770c99 100644
--- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
+++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c
@@ -155,6 +155,14 @@ unsigned int mod_freesync_calc_v_total_from_refresh(
 		v_total = div64_u64(div64_u64(((unsigned long long)(
 				frame_duration_in_ns) * (stream->timing.pix_clk_100hz / 10)),
 				stream->timing.h_total), 1000000);
+	} else if (refresh_in_uhz >= stream->timing.max_refresh_in_uhz) {
+		/* When the target refresh rate is the maximum panel refresh rate
+		 * round up the vtotal value to prevent off-by-one error causing
+		 * v_total_min to be below the panel's lower bound
+		 */
+		v_total = div64_u64(div64_u64(((unsigned long long)(
+				frame_duration_in_ns) * (stream->timing.pix_clk_100hz / 10)),
+				stream->timing.h_total) + (1000000 - 1), 1000000);
 	} else {
 		v_total = div64_u64(div64_u64(((unsigned long long)(
 				frame_duration_in_ns) * (stream->timing.pix_clk_100hz / 10)),
-- 
2.43.0