drm/amd/display: Fix P010, NV12, YUY2 scale down by four times failure

[WHY]
When performing 4:1 downscaling with subsampled formats,
the SPL remainder distribution logic (+1) overrides the
upper layer’s aligned width, resulting in odd segment
widths and causing hang.

The upper layer alignment ensures the width is sufficient
and even, so SPL should not modify it further.

[HOW]
In dc_spl.c within calculate_mpc_slice_in_timing_active,
add an extra condition: Skip the remainder distribution
(+1) when use_recout_width_aligned is true.This change
respects the upper layer’s alignment decision, prevents
odd widths, and is a minimal, safe fix.

Reviewed-by: Joshua Aberback <joshua.aberback@amd.com>
Signed-off-by: Kaier Hsueh <Kaier.Hsueh@amd.com>
Signed-off-by: Chenyu Chen <chen-yu.chen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/sspl/dc_spl.c b/drivers/gpu/drm/amd/display/dc/sspl/dc_spl.c
index f506ab7..d8aebaf 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/sspl/dc_spl.c
+++ b/drivers/gpu/drm/amd/display/dc/sspl/dc_spl.c
@@ -226,7 +226,8 @@ static struct spl_rect calculate_mpc_slice_in_timing_active(
        /* extra pixels in the division remainder need to go to pipes after
         * the extra pixel index minus one(epimo) defined here as:
         */
-       if (mpc_slice_idx > epimo && spl_in->basic_in.custom_width == 0) {
+       if ((use_recout_width_aligned == false) &&
+               mpc_slice_idx > epimo && spl_in->basic_in.custom_width == 0) {
                mpc_rec.x += mpc_slice_idx - epimo - 1;
                mpc_rec.width += 1;
        }