linux-kernel - [PATCH v2 3/3] drm/msm/dpu: Remove arbitrary limit of 1 interface in DSC topology

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250209-drm-msm-initial-dualpipe-dsc-fixes-v2-3-9a60184fdc36@somainline.org>
Date: Sun, 09 Feb 2025 22:42:54 +0100
From: Marijn Suijten <marijn.suijten@...ainline.org>
To: Rob Clark <robdclark@...il.com>, 
 Abhinav Kumar <quic_abhinavk@...cinc.com>, 
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, Sean Paul <sean@...rly.run>, 
 David Airlie <airlied@...il.com>, Vinod Koul <vkoul@...nel.org>, 
 Simona Vetter <simona@...ll.ch>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
 freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 Jordan Crouse <jordan@...micpenguin.net>, 
 ~postmarketos/upstreaming@...ts.sr.ht, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Martin Botka <martin.botka@...ainline.org>, 
 Jami Kettunen <jami.kettunen@...ainline.org>, 
 Konrad Dybcio <konrad.dybcio@....qualcomm.com>, 
 Marijn Suijten <marijn.suijten@...ainline.org>
Subject: [PATCH v2 3/3] drm/msm/dpu: Remove arbitrary limit of 1 interface
 in DSC topology

When DSC is enabled the number of interfaces is forced to be 1, and
documented that it is a "power-optimal" layout to use two DSC encoders
together with two Layer Mixers.  However, the same layout (two DSC
hard-slice encoders with two LMs) is also used when the display is
fed with data over two instead of one interface (common on 4k@...Hz
smartphone panels with Dual-DSI).  Solve this by simply removing the
num_intf = 1 assignment as the count is already calculated by computing
the number of physical encoders within the virtual encoder.

Fixes: 7e9cc175b159 ("drm/msm/disp/dpu1: Add support for DSC in topology")
Signed-off-by: Marijn Suijten <marijn.suijten@...ainline.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index b585cd17462345f94bcc2ddd57902cc7c312ae63..b0870318471bd7cceda70fd15ea7bcc8658af604 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -686,20 +686,21 @@ static struct msm_display_topology dpu_encoder_get_topology(
 
 	if (dsc) {
 		/*
-		 * Use 2 DSC encoders and 2 layer mixers per single interface
+		 * Use 2 DSC encoders, 2 layer mixers and 1 or 2 interfaces
 		 * when Display Stream Compression (DSC) is enabled,
 		 * and when enough DSC blocks are available.
 		 * This is power-optimal and can drive up to (including) 4k
 		 * screens.
 		 */
-		if (dpu_kms->catalog->dsc_count >= 2) {
+		WARN(topology.num_intf > 2,
+		     "DSC topology cannot support more than 2 interfaces\n");
+		if (intf_count >= 2 || dpu_kms->catalog->dsc_count >= 2) {
 			topology.num_dsc = 2;
 			topology.num_lm = 2;
 		} else {
 			topology.num_dsc = 1;
 			topology.num_lm = 1;
 		}
-		topology.num_intf = 1;
 	}
 
 	return topology;

-- 
2.48.1