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[129.46.232.65]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9260079070bsm2143165885a.40.2026.06.29.07.16.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Jun 2026 07:16:21 -0700 (PDT) From: Yongxing Mou To: Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Sean Paul , Marijn Suijten , David Airlie , Simona Vetter , Jessica Zhang Cc: linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org, Abhinav Kumar Subject: [PATCH RESEND v5 15/25] drm/msm/dp: add an API to initialize MST on sink side Date: Mon, 29 Jun 2026 22:14:36 +0800 Message-ID: <20260629-msm-dp-mst-v5-15-2ed6aee1867a@oss.qualcomm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260629-msm-dp-mst-v5-0-2ed6aee1867a@oss.qualcomm.com> References: <20260629-msm-dp-mst-v5-0-2ed6aee1867a@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1782742144; l=3085; i=yongxing.mou@oss.qualcomm.com; s=20250910; h=from:subject:message-id; bh=rWGVRQL4yrr/+OcPJZsE2NbhmKlJWDJ86JwhFSr0tHA=; b=zp/0usdQR549mw+/NeCy7PT7dzFTuN9P/wjXLseMDCh/AeFJowZcElLpVJbjhgNu3r6hZsQRG HKc7XxlHUmqDGXWEc7sKzW7mjBNDpmrUJJL+n/QirG0QUBuWI1toBbn X-Developer-Key: i=yongxing.mou@oss.qualcomm.com; a=ed25519; pk=rAy5J1eP+V7OXqH5FJ7ngMCtUrnHhut30ZTldOj52UM= Content-Transfer-Encoding: 8bit X-Proofpoint-ORIG-GUID: UrM1JWwctSyIo5v_a6izp3VQiekrcBZS X-Authority-Analysis: v=2.4 cv=Z4Hc2nRA c=1 sm=1 tr=0 ts=6a427e36 cx=c_pps a=qKBjSQ1v91RyAK45QCPf5w==:117 a=C3Dk8TwHQYyIj7nOf9RCJw==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=gowsoOTTUOVcmtlkKump:22 a=COk6AnOGAAAA:8 a=EUspDBNiAAAA:8 a=vCCEq3Mv4WXTdc8uXsoA:9 a=QEXdDO2ut3YA:10 a=NFOGd7dJGGMPyQGDc5-O:22 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjI5MDExOCBTYWx0ZWRfX1kw2TB5iUHq8 dTTllvnk2pznZSMFcRAmTJth9EIMcxo3wTUvhX1qVTglmcYa4IhETO7Vr6CL4rI///O2Q1RD4sc IITuceKJ5dfiG0nEHFTNZOBAEMmZmN4= X-Proofpoint-GUID: UrM1JWwctSyIo5v_a6izp3VQiekrcBZS X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjI5MDExOCBTYWx0ZWRfX8NYAOi1Aao+9 NA4svHw+9z/E7dxNoAE+i6Ojz0Y1QwU8tYG9O+GmvWAwbZRBl1VTlQLeO5HGloLcUtl/gxNBvMb BDmFP6bL4MNmKg4x/JylhtIbMe218Bl2T6nCf/u6Fy9QfWS3zsAdMRf4nPyqiBimfEQ725ofTFw F8goHTgNf+pwxqXllejZZOt3HX94i5pY8YRmlkYfqdSfMWSLofkXPY9lgfxwwQHQPE5TJDb/txb SXHYpR/Wphvll6hg5zLRJpgT8OftJolne6J5MLpsiy/04lryN6lFbngGwgYWXIH5mpllNYvMDLz sFB5ZzrJvHXhs/Xq961+6kUsJr4jEzox1cOOgQZET5az7gbsNgn5Vxfv40dNf6ZdXAa8bvVdShm +3oArOog9QLQZ+akpAupbQoh20kWr1iLL7v8hhlwCvn06d8eJ/DsGEE8REyM2UQMXXQwXgQmVOa PGNc0uE7Y4k4mDeDe3Q== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-29_03,2026-06-26_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 lowpriorityscore=0 priorityscore=1501 bulkscore=0 spamscore=0 impostorscore=0 phishscore=0 clxscore=1015 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606290118 From: Abhinav Kumar If the DP controller is capable of supporting multiple streams then initialize the DP sink in MST mode by programming the DP_MSTM_CTRL DPCD register to enable MST mode. Signed-off-by: Abhinav Kumar Signed-off-by: Yongxing Mou --- drivers/gpu/drm/msm/dp/dp_display.c | 48 +++++++++++++++++++++++++++++++------ 1 file changed, 41 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c index 5786e598a406..c3be656f10ee 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include "msm_drv.h" @@ -270,6 +271,31 @@ static int msm_dp_display_lttpr_init(struct msm_dp_display_private *dp, u8 *dpcd return lttpr_count; } +static void msm_dp_display_mst_init(struct msm_dp_display_private *dp) +{ + u8 old_mstm_ctrl; + struct msm_dp *msm_dp = &dp->msm_dp_display; + int ret; + + /* clear sink MST state */ + drm_dp_dpcd_read_byte(dp->aux, DP_MSTM_CTRL, &old_mstm_ctrl); + + ret = drm_dp_dpcd_write_byte(dp->aux, DP_MSTM_CTRL, 0); + if (ret < 0) { + DRM_ERROR("failed to clear DP_MSTM_CTRL, ret=%d\n", ret); + return; + } + + ret = drm_dp_dpcd_write_byte(dp->aux, DP_MSTM_CTRL, + DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC); + if (ret < 0) { + DRM_ERROR("sink MST enablement failed\n"); + return; + } + + msm_dp->mst_active = true; +} + static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp) { struct drm_connector *connector = dp->msm_dp_display.connector; @@ -288,14 +314,19 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp) if (rc) goto end; - drm_edid = drm_edid_read_ddc(connector, &dp->aux->ddc); - drm_edid_connector_update(connector, drm_edid); + if (!(dp->max_stream > 1) || !drm_dp_read_mst_cap(dp->aux, dp->panel->dpcd)) { + drm_edid = drm_edid_read_ddc(connector, &dp->aux->ddc); + drm_edid_connector_update(connector, drm_edid); - if (!drm_edid) { - DRM_ERROR("panel edid read failed\n"); - /* check edid read fail is due to unplug */ - if (!msm_dp_aux_is_link_connected(dp->aux)) - return -ETIMEDOUT; + if (!drm_edid) { + DRM_ERROR("panel edid read failed\n"); + /* check edid read fail is due to unplug */ + if (!msm_dp_aux_is_link_connected(dp->aux)) + return -ETIMEDOUT; + } + + if (rc) + goto end; } msm_dp_link_process_request(dp->link); @@ -317,6 +348,9 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp) */ msm_dp_link_psm_config(dp->link, &dp->panel->link_info, false); + if (dp->max_stream > 1 && drm_dp_read_mst_cap(dp->aux, dp->panel->dpcd)) + msm_dp_display_mst_init(dp); + msm_dp_link_reset_phy_params_vx_px(dp->link); end: -- 2.43.0