From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1B14DC55196 for ; Mon, 3 Aug 2026 19:02:34 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 707A410E072; Mon, 3 Aug 2026 19:02:33 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="je4MlngN"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4A9C410E072 for ; Mon, 3 Aug 2026 19:02:32 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 029F74066F; Mon, 3 Aug 2026 19:02:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52E3D1F000E9; Mon, 3 Aug 2026 19:02:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785783751; bh=zaPGMlQUaq9J2FWn4IXfo4a8GLR6eQyMDMz2OWTQgkc=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=je4MlngNyeAGvlVIH3lKFk0CaSxYyClC9lMouPQmXSInSe/vXnYNvesnQ5rnk9ZYZ Z61bIprJnmf9n//3GIgy3gcWF7kNp0yl4P7JphPJge6NFSi8981BhQS3cBEO1LXNxq rCplG/iTHt5F4vYINJW/8x+dZRQ2Fb8KDxfkMho7lx/oM2v1XU5HGHOcRKWdsHqscu PDiIZeckmMH2QSFHU4/iTFmwvzAshA30pCDMgGoHO+9wVWKx0vJRWhg4R6JI0htTKH C7MfXSP46On1sEutnDrSL+2Ty0gDTE11Pp83dVRWRSQFVg1I7K51e3144OayWnnXa8 cruZhcZaw7EHA== From: sashiko-bot@kernel.org Subject: Re: [PATCH v9 18/22] drm/bridge: synopsys: dw-dp: Drop useless reservation of first slot To: "Sebastian Reichel" Cc: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, robh@kernel.org, conor+dt@kernel.org In-Reply-To: <20260803-synopsys-dw-dp-improvements-v9-18-2e6e46135312@collabora.com> References: <20260803-synopsys-dw-dp-improvements-v9-0-2e6e46135312@collabora.com> <20260803-synopsys-dw-dp-improvements-v9-18-2e6e46135312@collabora.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 03 Aug 2026 19:02:30 +0000 Message-Id: <20260803190231.52E3D1F000E9@smtp.kernel.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] Unbalanced resource lifecycle operations on error paths in dw_dp_b= ridge_atomic_enable -- --- Patch [18]: [PATCH v9 18/22] drm/bridge: synopsys: dw-dp: Drop useless = reservation of first slot --- commit 7167a1f6669c417c9c943c6894f5b2a33b32f0bf Author: Sebastian Reichel drm/bridge: synopsys: dw-dp: Drop useless reservation of first slot This commit removes the reservation of the first SDP slot in the atomic_ena= ble path. The reservation was unclear in origin and could race with audio SDP reservation features. > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/br= idge/synopsys/dw-dp.c > index 19b6c11f672f9..05d3485a4d8db 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c > @@ -1706,9 +1706,6 @@ static void dw_dp_bridge_atomic_enable(struct drm_b= ridge *bridge, > return; > } > =20 > - scoped_guard(mutex, &dp->sdp_lock) > - set_bit(0, dp->sdp_reg_bank); > - > ret =3D dw_dp_link_enable(dp); > if (ret < 0) { > dev_err(dp->dev, "failed to enable link: %d\n", ret); [Severity: High] Does this error path leave dp->pm_active =3D true while the PHY is powered = off? If dw_dp_link_enable() fails, it cleans up by calling phy_power_off(): dw_dp_link_enable() { ... err_phy_power_off: phy_power_off(dp->phy); return ret; } However, when we return early here, dp->pm_active remains true. Because the DRM core considers the atomic commit successful even if the bridge enable callback returns early, a subsequent mode-set or display-off operation will invoke dw_dp_bridge_atomic_disable(). Because dp->pm_active is true, the disable path proceeds to call dw_dp_link_disable(), which unconditionally calls phy_power_off() again: dw_dp_bridge_atomic_disable() { if (!dp->pm_active) return; dp->pm_active =3D false; ... dw_dp_link_disable(dp); } dw_dp_link_disable() { ... phy_power_off(dp->phy); ... } Can this unbalanced phy_power_off() cause the PHY power count to go negativ= e, causing subsequent power-on attempts to silently fail? This same unbalanced teardown could also occur earlier in this function if drm_atomic_get_new_connector_for_encoder() or drm_atomic_get_new_connector_state() return NULL, as dp->pm_active is set to true before those checks. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260803-synopsys-d= w-dp-improvements-v9-0-2e6e46135312@collabora.com?part=3D18