[PATCH 8/9] drm/i915/dsc: Account for Odd pixel removal

[Ankit Nautiyal <ankit.k.nautiyal@intel.com>]

With 3 DSC engines we can support 12 slices. With ultra joiner
usecase while dividing the width into 12 slices, we might
end up having odd number of pixels per pipe.
As per Bspec, pipe src size should be even, so an extra pixel is added
in each pipe. For Pipe A and C the odd pixel is added at the end of
pipe and for Pipe B and D it is added at the beginning of the pipe.
This extra pixel needs to be dropped in Splitter hardware.
So account for odd pixel removal while programming DSS CTL.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vdsc.c | 26 +++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
index f58dac630bb8..d2d712545450 100644
--- a/drivers/gpu/drm/i915/display/intel_vdsc.c
+++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
@@ -768,6 +768,26 @@ void intel_uncompressed_joiner_enable(const struct intel_crtc_state *crtc_state)
 	}
 }
 
+/*
+ * With 12 slices, there can be a case where the src width is odd.
+ * As per Bspec the src width should be even, so an extra Odd Pixel is
+ * programmed in Pipe in such cases. This extra pixel needs to be
+ * dropped in Splitter HW.
+ */
+static
+bool intel_dsc_need_odd_pixel_removal(const struct intel_crtc_state *crtc_state)
+{
+	int pipe_src_w = drm_rect_width(&crtc_state->pipe_src);
+
+	if (intel_crtc_num_joined_pipes(crtc_state) != 4)
+		return false;
+
+	if ((pipe_src_w + crtc_state->dsc.pixel_replication_count) % 4)
+		return true;
+
+	return false;
+}
+
 void intel_dsc_enable(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
@@ -806,6 +826,12 @@ void intel_dsc_enable(const struct intel_crtc_state *crtc_state)
 			dss_ctl1_val |= PRIMARY_BIG_JOINER_ENABLE;
 	}
 
+	if (intel_dsc_need_odd_pixel_removal(crtc_state)) {
+		dss_ctl2_val |= ODD_PIXEL_REMOVAL;
+		if (crtc->pipe == PIPE_A || crtc->pipe == PIPE_C)
+			dss_ctl2_val |= ODD_PIXEL_REMOVAL_CONFIG_EOL;
+	}
+
 	if (crtc_state->dsc.pixel_replication_count)
 		dss_ctl3_val = DSC_PIXEL_REPLICATION(crtc_state->dsc.pixel_replication_count);
 
-- 
2.45.2