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 48CEB606A31A for ; Thu, 29 Oct 2026 08:12:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mWLFSnDC Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 83CEA11201C; Thu, 29 Oct 2026 08:12:41 +0000 (UTC) Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id AFFDD11201C for ; Thu, 29 Oct 2026 08:12:35 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id EC543600D1 for ; Thu, 29 Oct 2026 08:12:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 816EC1F01825; Thu, 29 Oct 2026 08:12:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793261554; bh=xFiw3q2XJSmE6+HSvlKGZlbAB2GSTJJVlN8Yf88idJE=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=mWLFSnDCsRmwx0d0jmcAIrVORcczQ/0QdHx+98TiniSPgyGExjn0jjiZiOs8mNasw gpRk7dSPYg9dMXJF21ciercDdk1fN956AsMggtff9CR/D7vscfcUu3oIHqmpZJUGrz zLcCaoRoiH1mJA0kKOwFzY+ux/OREyljqVLZkOJLhdphRoYtWyfD/HKb1/Q75GQ2g+ aeZnybXeNnh2vTcHeu2e30L2OPyPwBaUO7paF42IuonA7NzH6HaOitDTpfPhh2fEbg XruDrf3knw2jfp+ojfgqHkYdRSvDbQ4120d6CFdUKeH8P03NJQ2eeG9mUJ2F5OLm6h E4NY7UYL9grPw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v7 34/34] drm/bridge: sii902x: Implement hw state readout To: "Maxime Ripard" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20261029-drm-state-readout-v7-34-25e5163d75c3@kernel.org> References: <20261029-drm-state-readout-v7-0-25e5163d75c3@kernel.org> <20261029-drm-state-readout-v7-34-25e5163d75c3@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 29 Oct 2026 08:12:34 +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 2 potential issue(= s) to consider: - [High] drm/bridge: sii902x: missing mutex lock in readout callbacks - [Medium] drm/bridge: sii902x: ignored regmap_test_bits() error in readout= _state() -- commit ce74a42cab42e6bb481c531e7732368f37a0e27c Author: Maxime Ripard drm/bridge: sii902x: Implement hw state readout This commit implements hardware state readout callbacks for the sii902x bridge driver and enables DRM_BRIDGE_OP_CONNECTOR_HW_READOUT. > diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/si= i902x.c > index e067c0636e7f5..ab5ffcf6882f2 100644 > --- a/drivers/gpu/drm/bridge/sii902x.c > +++ b/drivers/gpu/drm/bridge/sii902x.c [ ... ] > @@ -537,6 +539,89 @@ sii902x_bridge_mode_valid(struct drm_bridge *bridge, > return MODE_OK; > } > =20 > +static int > +sii902x_bridge_connector_readout(struct drm_bridge *bridge, > + struct drm_atomic_sro_state *state, > + struct drm_connector_state *conn_state) > +{ > + struct sii902x *sii902x =3D bridge_to_sii902x(bridge); > + struct drm_connector *connector =3D conn_state->connector; > + struct drm_crtc_state *crtc_state; > + struct drm_encoder *encoder; > + struct drm_crtc *crtc; > + int ret; > + > + ret =3D regmap_test_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA, SII902= X_SYS_CTRL_PWR_DWN); [Severity: High] Should sii902x_bridge_connector_readout() and sii902x_bridge_readout_state() hold sii902x->mutex around their regmap_test_bits() calls? In drivers/gpu/drm/bridge/sii902x.c, sii902x_regmap_config disables regmap's internal locking: static const struct regmap_config sii902x_regmap_config =3D { .reg_bits =3D 8, .val_bits =3D 8, .disable_locking =3D true, /* struct sii902x mutex should be enough */ ... }; All other post-init regmap callers in this driver (such as sii902x_interrupt(), sii902x_detect(), sii902x_edid_read(), sii902x_bridge_mode_set(), and the audio callbacks) serialize access via sii902x->mutex. Without holding sii902x->mutex here, an unlocked regmap_test_bits() during initial state readout or post-commit drm_atomic_sro_readout_and_compare() can race with concurrent HPD interrupt handling, DDC operations, or ALSA audio callbacks and clobber regmap's shared map->work_buf or interleave I2C sequences. > + /* I2C error */ > + if (ret < 0) > + return ret; > + /* Device is powered down, nothing to read out */ > + if (ret) > + return 0; [ ... ] > +static int sii902x_bridge_readout_state(struct drm_bridge *bridge, > + struct drm_atomic_sro_state *state, > + struct drm_bridge_state *bridge_state, > + struct drm_crtc_state *crtc_state, > + struct drm_connector_state *conn_state) > +{ > + struct sii902x *sii902x =3D bridge_to_sii902x(bridge); > + u32 input_format; > + > + if (regmap_test_bits(sii902x->regmap, SII902X_SYS_CTRL_DATA, SII902X_SY= S_CTRL_PWR_DWN)) > + return 0; [Severity: Medium] What happens in sii902x_bridge_readout_state() if regmap_test_bits() fails with a negative error code? Because a negative errno is non-zero, the if condition evaluates to true and sii902x_bridge_readout_state() returns 0 as though the device were powered down, leaving bridge_state->input_bus_cfg and bridge_state->output_bus_cfg unpopulated. Should this check for ret < 0 and propagate the error like sii902x_bridge_connector_readout() does above? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261029-drm-state-= readout-v7-0-25e5163d75c3@kernel.org?part=3D34