drm/amd/display: Fix vupdate and vline position calculation

[how]
Large deltas for periodic interrupts could result in the interrupt not
being programmed properly and thus not firing.

[why]
Add proper wrap-around support for calculating VUPDATE and VLINE
positions.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 4390f6d..f4b3ec3 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -3818,28 +3818,14 @@ void dcn10_calc_vupdate_position(
                uint32_t *start_line,
                uint32_t *end_line)
 {
-       const struct dc_crtc_timing *dc_crtc_timing = &pipe_ctx->stream->timing;
-       int vline_int_offset_from_vupdate =
-                       pipe_ctx->stream->periodic_interrupt.lines_offset;
-       int vupdate_offset_from_vsync = dc->hwss.get_vupdate_offset_from_vsync(pipe_ctx);
-       int start_position;
-
-       if (vline_int_offset_from_vupdate > 0)
-               vline_int_offset_from_vupdate--;
-       else if (vline_int_offset_from_vupdate < 0)
-               vline_int_offset_from_vupdate++;
+       const struct dc_crtc_timing *timing = &pipe_ctx->stream->timing;
+       int vupdate_pos = dc->hwss.get_vupdate_offset_from_vsync(pipe_ctx);
 
-       start_position = vline_int_offset_from_vupdate + vupdate_offset_from_vsync;
-
-       if (start_position >= 0)
-               *start_line = start_position;
+       if (vupdate_pos >= 0)
+               *start_line = vupdate_pos - ((vupdate_pos / timing->v_total) * timing->v_total);
        else
-               *start_line = dc_crtc_timing->v_total + start_position - 1;
-
-       *end_line = *start_line + 2;
-
-       if (*end_line >= dc_crtc_timing->v_total)
-               *end_line = 2;
+               *start_line = vupdate_pos + ((-vupdate_pos / timing->v_total) + 1) * timing->v_total - 1;
+       *end_line = (*start_line + 2) % timing->v_total;
 }
 
 static void dcn10_cal_vline_position(
@@ -3848,23 +3834,27 @@ static void dcn10_cal_vline_position(
                uint32_t *start_line,
                uint32_t *end_line)
 {
-       switch (pipe_ctx->stream->periodic_interrupt.ref_point) {
-       case START_V_UPDATE:
-               dcn10_calc_vupdate_position(
-                               dc,
-                               pipe_ctx,
-                               start_line,
-                               end_line);
-               break;
-       case START_V_SYNC:
+       const struct dc_crtc_timing *timing = &pipe_ctx->stream->timing;
+       int vline_pos = pipe_ctx->stream->periodic_interrupt.lines_offset;
+
+       if (pipe_ctx->stream->periodic_interrupt.ref_point == START_V_UPDATE) {
+               if (vline_pos > 0)
+                       vline_pos--;
+               else if (vline_pos < 0)
+                       vline_pos++;
+
+               vline_pos += dc->hwss.get_vupdate_offset_from_vsync(pipe_ctx);
+               if (vline_pos >= 0)
+                       *start_line = vline_pos - ((vline_pos / timing->v_total) * timing->v_total);
+               else
+                       *start_line = vline_pos + ((-vline_pos / timing->v_total) + 1) * timing->v_total - 1;
+               *end_line = (*start_line + 2) % timing->v_total;
+       } else if (pipe_ctx->stream->periodic_interrupt.ref_point == START_V_SYNC) {
                // vsync is line 0 so start_line is just the requested line offset
-               *start_line = pipe_ctx->stream->periodic_interrupt.lines_offset;
-               *end_line = *start_line + 2;
-               break;
-       default:
+               *start_line = vline_pos;
+               *end_line = (*start_line + 2) % timing->v_total;
+       } else
                ASSERT(0);
-               break;
-       }
 }
 
 void dcn10_setup_periodic_interrupt(