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 42917606A31C for ; Tue, 10 Nov 2026 05:25:59 +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=LEcnIXoF Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 971BC10EDCA; Tue, 10 Nov 2026 05:25:53 +0000 (UTC) Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id B71B710EDCA for ; Tue, 10 Nov 2026 05:25:46 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 3B3B36123A; Tue, 10 Nov 2026 05:25:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C24C01F0089F; Tue, 10 Nov 2026 05:25:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794288345; bh=P1N9xAVhds+O9wb4WTriyPNBUP3WPAIDoxZfYdFVWBQ=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=LEcnIXoFhVa/+tY5Ihy7qDC0UqV960te0swxhSUQOiv4AJ5AvV+TO3aT2PG4oAcrK VN08Sa5LFdSG7JM4X0GMnoSjsWf5gintIz8HWNu7hZz/0j3B/Opa7x3mpDs0+iz1At luofccJndzzuBOyTt3nO+uBsN8RNAeQKffw+ZsmImUQMoOfEuOwxQsCgSPxRhvwVOB tyCY+yIRnmhfY+WP6U1SqLPlzlj3pqGY8V19ZF1XFpGzeaczk6G9OMrSAv5s6CwJ/x FZMXmEG3Nuf6CEqA5r/PtB/xCeHUYH+cqQidhtLOrQq8RLecgoEdRTitPyjZNbk5Xv zLyM/prNbImGw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v8 23/29] drm/msm/dp: mark the SST bridge disconnected when mst is active To: "Yongxing Mou" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20261110-msm-dp-mst-v8-23-d040fb33db5f@oss.qualcomm.com> References: <20261110-msm-dp-mst-v8-0-d040fb33db5f@oss.qualcomm.com> <20261110-msm-dp-mst-v8-23-d040fb33db5f@oss.qualcomm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 10 Nov 2026 05:25:45 +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: - [Medium] drm/msm/dp: unlocked mst_active check in msm_dp_bridge_detect() -- commit 485c09f4556b36ae4b303173f11055d3729894af Author: Abhinav Kumar drm/msm/dp: mark the SST bridge disconnected when mst is active This commit returns disconnected from msm_dp_bridge_detect() for the SST bridge when dp->mst_active is set. > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp= /dp_display.c > index b4e788d1f611d..f87eea19c4f58 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -976,7 +976,11 @@ enum drm_connector_status msm_dp_bridge_detect(struc= t drm_bridge *bridge, > =20 > priv =3D container_of(dp, struct msm_dp_display_private, msm_dp_display= ); > =20 > + if (dp->mst_active) > + return status; > + > guard(mutex)(&priv->plugged_lock); [Severity: Medium] Should dp->mst_active be checked after acquiring priv->plugged_lock, as msm_dp_irq_hpd_handle() does? drm_bridge_connector_hpd_notify() runs without dev->mode_config.mutex, so priv->plugged_lock is what serializes HPD plug handling against concurrent connector probing: CPU0 CPU1 msm_dp_hpd_plug_handle() mutex_lock(&dp->plugged_lock) msm_dp_display_process_hpd_high() msm_dp_bridge_detect() if (dp->mst_active) // false mutex_lock(&priv->plugged_lock) ... msm_dp_display_mst_enable() msm_dp->mst_active =3D true dp->plugged =3D true mutex_unlock(&dp->plugged_lock) pm_runtime_resume_and_get(...) ... priv->plugged =3D true // returns without pm_runtime_put_s= ync // <-- leaks runtime PM reference Once msm_dp_bridge_detect() enters the SST detection path after MST has been enabled, a successful DPCD read leaves an extra runtime PM reference that msm_dp_hpd_unplug_handle() never drops, while a failed AUX transfer clears priv->plugged and causes msm_dp_hpd_unplug_handle() to bail out without disabling MST. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110-msm-dp-mst= -v8-0-d040fb33db5f@oss.qualcomm.com?part=3D23