From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B58B4606A31C for ; Tue, 10 Nov 2026 05:29:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FDZKQ32n Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 00FA110EDD0; Tue, 10 Nov 2026 05:29:23 +0000 (UTC) Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id C8BDE10EDD0 for ; Tue, 10 Nov 2026 05:29:16 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 714CD43512; Tue, 10 Nov 2026 05:29:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B9971F0089F; Tue, 10 Nov 2026 05:29:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794288556; bh=qURFCHI0mJ0MIh7/gROc2ImEsoDzhRY/a8vYxxn2uLg=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=FDZKQ32nttSxtgNRpDmeH58uXXNCVRd+rkuaglcWBZOfSptCDW8fb6oKBVK7u9STO 7Iaqp1+kcy7SDBWcBxz+M8UN3r5y1fN90OwwSa1LX4+Ntx0zvy82MPQAcihT68p7oY PnGj/FFWNaIKwET/u+nnMGX8uI7EmmmIOPgBB6GYxMQDS1iH+g0A+JN56Vt494QQmp BC3VYGvYUsMPz28dLMbKm03UlViWY3XfQK6TXdM2cFzf09eBOqBc48MaMTQCTUSF+4 Dd/MvrqjMwxezrw3qbgp+IwMT/IOJklXCu0I+cvJxFk0O3vvLBHnNPMTRLkImt/+P7 o/2ahXlM6Y7Cw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v8 25/29] drm/msm/dp: mark the SST bridge disconnected when an MST-capable sink is present To: "Yongxing Mou" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20261110-msm-dp-mst-v8-25-d040fb33db5f@oss.qualcomm.com> References: <20261110-msm-dp-mst-v8-0-d040fb33db5f@oss.qualcomm.com> <20261110-msm-dp-mst-v8-25-d040fb33db5f@oss.qualcomm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 10 Nov 2026 05:29:15 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "dri-devel" X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 1 potential issue to consider: - [High] drm/msm/dp: msm_dp_bridge_detect() sets plugged and blocks boot MST enable -- commit 6523f8221c3f008ff483a89b251f28757e2c5462 Author: Abhinav Kumar drm/msm/dp: mark the SST bridge disconnected when an MST-capable sink is pr= esent This commit returns connector_status_disconnected from msm_dp_bridge_detect() when the controller supports multi-stream and the connected sink reports MST capability. > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp= /dp_display.c > index eeb0e04949000..8ea3d258a98f3 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -1063,6 +1063,11 @@ enum drm_connector_status msm_dp_bridge_detect(str= uct drm_bridge *bridge, > status =3D connector_status_disconnected; > } > =20 > + /* Mark SST connector as disconnected in DP boot-up case */ > + if (msm_dp_ctrl_get_stream_cnt(priv->ctrl) > 1 && > + drm_dp_read_mst_cap(priv->aux, dpcd) =3D=3D DRM_DP_MST) > + status =3D connector_status_disconnected; [Severity: High] Does returning connector_status_disconnected here after setting priv->plugged =3D true prevent msm_dp_hpd_plug_handle() from enabling MST on boot? When msm_dp_bridge_detect() runs before msm_dp_hpd_plug_handle() at boot, it sets priv->plugged =3D true earlier in the function and then overrides status to connector_status_disconnected without enabling MST. When the HPD plug notification subsequently runs, msm_dp_hpd_plug_handle() sees dp->plugged is already true and returns early: drivers/gpu/drm/msm/dp/dp_display.c:msm_dp_hpd_plug_handle() { ... guard(mutex)(&dp->plugged_lock); if (dp->plugged) return 0; ... ret =3D msm_dp_display_process_hpd_high(dp); ... } As a result, msm_dp_display_process_hpd_high() and msm_dp_display_mst_enable() are never called, leaving the SST connector disconnected and the MST topology manager inactive until the cable is replugged. In addition, if msm_dp_display_mst_enable() fails during msm_dp_display_process_hpd_high(), unconditionally returning connector_status_disconnected here prevents falling back to SST. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110-msm-dp-mst= -v8-0-d040fb33db5f@oss.qualcomm.com?part=3D25