From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> commit bf52dc49ba0101f648b4c3ea26b812061406b0d4 upstream. Don't zero out the watermarks for the Y plane since we've already computed them when computing the UV plane's watermarks (since the UV plane always appears before ethe Y plane when iterating through the planes). This leads to allocating no DDB for the Y plane since .min_ddb_alloc also gets zeroed. And that of course leads to underruns when scanning out planar formats. Cc: stable@xxxxxxxxxxxxxxx Cc: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> Fixes: dbf71381d733 ("drm/i915: Nuke intel_atomic_crtc_state_for_each_plane_state() from skl+ wm code") Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20210327005945.4929-1-ville.syrjala@xxxxxxxxxxxxxxx Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> (cherry picked from commit f99b805fb9413ff007ca0b6add871737664117dd) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_pm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5539,12 +5539,12 @@ static int icl_build_plane_wm(struct int struct skl_plane_wm *wm = &crtc_state->wm.skl.raw.planes[plane_id]; int ret; - memset(wm, 0, sizeof(*wm)); - /* Watermarks calculated in master */ if (plane_state->planar_slave) return 0; + memset(wm, 0, sizeof(*wm)); + if (plane_state->planar_linked_plane) { const struct drm_framebuffer *fb = plane_state->hw.fb; enum plane_id y_plane_id = plane_state->planar_linked_plane->id;