linux-kernel - [PATCH v2 09/11] drm/msm/disp/dpu1: Add support for DSC in topology

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Message-Id: <20211007070900.456044-10-vkoul@kernel.org>
Date:   Thu,  7 Oct 2021 12:38:58 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Rob Clark <robdclark@...il.com>
Cc:     linux-arm-msm@...r.kernel.org,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Vinod Koul <vkoul@...nel.org>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jonathan Marek <jonathan@...ek.ca>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Abhinav Kumar <abhinavk@...eaurora.org>,
        Jeffrey Hugo <jeffrey.l.hugo@...il.com>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org
Subject: [PATCH v2 09/11] drm/msm/disp/dpu1: Add support for DSC in topology

For DSC to work we typically need a 2,2,1 configuration. This should
suffice for resolutions upto 4k. For more resolutions like 8k this won't
work.

Also, it is better to use 2 LMs and DSC instances as half width results
in lesser power consumption as compared to single LM, DSC at full width.

The panel has been tested only with 2,2,1 configuration, so for
now we blindly create 2,2,1 topology when DSC is enabled

Co-developed-by: Abhinav Kumar <abhinavk@...eaurora.org>
Signed-off-by: Abhinav Kumar <abhinavk@...eaurora.org>
Signed-off-by: Vinod Koul <vkoul@...nel.org>
---
Changes since
RFC:
 - Add more details in changelog

 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index aac51c1bdf94..70f57a071165 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -538,6 +538,8 @@ static struct msm_display_topology dpu_encoder_get_topology(
 			struct drm_display_mode *mode)
 {
 	struct msm_display_topology topology = {0};
+	struct drm_encoder *drm_enc;
+	struct msm_drm_private *priv;
 	int i, intf_count = 0;
 
 	for (i = 0; i < MAX_PHYS_ENCODERS_PER_VIRTUAL; i++)
@@ -572,8 +574,22 @@ static struct msm_display_topology dpu_encoder_get_topology(
 	topology.num_enc = 0;
 	topology.num_intf = intf_count;
 
+	drm_enc = &dpu_enc->base;
+	priv = drm_enc->dev->dev_private;
+	if (priv && priv->dsc) {
+		/* In case of Display Stream Compression DSC, we would use
+		 * 2 encoders, 2 line mixers and 1 interface
+		 * this is power optimal and can drive upto (including) 4k
+		 * screens
+		 */
+		topology.num_enc = 2;
+		topology.num_intf = 1;
+		topology.num_lm = 2;
+	}
+
 	return topology;
 }
+
 static int dpu_encoder_virt_atomic_check(
 		struct drm_encoder *drm_enc,
 		struct drm_crtc_state *crtc_state,
-- 
2.31.1