From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29B601FBEA4; Mon, 2 Dec 2024 10:23:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733135037; cv=none; b=mudUlAijQtcQFX8F/2W1iCd9LJRZI3qguV5vcbEzcvI2Kxbu2pNwxrG2JLzTF2dgMsDglweG5vItG7VoasnewucQHggNu9US1kL1l76s2a0aVGrTdFjde9zC/ZDZJy0bNJxfxC0W9hrR3NlhK6DkMMSFLIf5MOpLO2XvThpqoa8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733135037; c=relaxed/simple; bh=LoFYJIJMK9Q6i+Gw0XK8Wb/1ESu9maODEfjoY8fwwDs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=bMCo52LEBYCvyrm/HJ9G9CPff65K0OKDsJlODFw/9ftoHeBvr2JBWqADwwD9vzorGtRqf/z16+NwpDddzAS/NMJkYddRhPnXlRtfQgF4UdHUl15LhvLoWcifgDJVIUWo09YSU/3WhX4WJQtxZPYAzGu2EMF+F+1bvcm7AAXlVFs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=iTK/DpFz; arc=none smtp.client-ip=192.198.163.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="iTK/DpFz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1733135035; x=1764671035; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=LoFYJIJMK9Q6i+Gw0XK8Wb/1ESu9maODEfjoY8fwwDs=; b=iTK/DpFzfn5abOUAh9iw/IW5OYc9PadyBwWm5Dp591RSMdMhF3PuCqau LdIH6EYj7DjvzpNg+VDhrtDZMT60OhTRN7udpeqtPFVrcTbC2HcMWsgTr X4ag54pqD0ivLZetVdpYLGaanVsyhcbAfg1GhajVEziv3hE+jUW+8gzLg U8w0PvwgY/4V9qMcW2JdOT2rxQFxHk17bVR+Zm1QPgL9RL+olLUSyH7av jVe+Noi/3VcsHQ9h0EEzVx80oWh/tbtotRR0VK44Opx6wkEDXT7tsJea5 F3Cv6V6yDn+TwIW/h4GtE/WWZy6d5bEtQ75wAAapxdOugqQvnYnOCJEGN g==; X-CSE-ConnectionGUID: J3lvAiUDTrWXZ5k/F6lTog== X-CSE-MsgGUID: bDvJbC88TDqp1OR3Gr2C8g== X-IronPort-AV: E=McAfee;i="6700,10204,11273"; a="58686704" X-IronPort-AV: E=Sophos;i="6.12,202,1728975600"; d="scan'208";a="58686704" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Dec 2024 02:23:54 -0800 X-CSE-ConnectionGUID: UHu/FGD7RLStnnYdm2d4Lg== X-CSE-MsgGUID: M4511x8/R/qE4ZFNnmbAHg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,202,1728975600"; d="scan'208";a="97836221" Received: from slindbla-desk.ger.corp.intel.com (HELO localhost) ([10.245.246.77]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Dec 2024 02:23:41 -0800 From: Jani Nikula To: Dmitry Baryshkov , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Harry Wentland , Leo Li , Rodrigo Siqueira , Alex Deucher , Christian =?utf-8?Q?K=C3=B6nig?= , Xinhui Pan , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Phong LE , Inki Dae , Seung-Woo Kim , Kyungmin Park , Krzysztof Kozlowski , Alim Akhtar , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , Rob Clark , Abhinav Kumar , Sean Paul , Marijn Suijten , Alain Volmat , Raphael Gallais-Pou , Dave Stevenson , =?utf-8?Q?Ma=C3=ADra?= Canal , Raspberry Pi Kernel Maintenance Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org Subject: Re: [PATCH 01/10] drm/connector: add mutex to protect ELD from concurrent access In-Reply-To: <20241201-drm-connector-eld-mutex-v1-1-ba56a6545c03@linaro.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20241201-drm-connector-eld-mutex-v1-0-ba56a6545c03@linaro.org> <20241201-drm-connector-eld-mutex-v1-1-ba56a6545c03@linaro.org> Date: Mon, 02 Dec 2024 12:23:29 +0200 Message-ID: <87r06q5qou.fsf@intel.com> Precedence: bulk X-Mailing-List: linux-samsung-soc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Sun, 01 Dec 2024, Dmitry Baryshkov wrote: > The connector->eld is accessed by the .get_eld() callback. This access > can collide with the drm_edid_to_eld() updating the data at the same > time. Add drm_connector.eld_mutex to protect the data from concurrenct > access. Individual drivers are not updated (to reduce possible issues > while applying the patch), maintainers are to find a best suitable way > to lock that mutex while accessing the ELD data. Missed clear_eld(). BR, Jani. > > Signed-off-by: Dmitry Baryshkov > --- > drivers/gpu/drm/drm_connector.c | 1 + > drivers/gpu/drm/drm_edid.c | 4 ++++ > include/drm/drm_connector.h | 5 ++++- > 3 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index fc35f47e2849ed6786d6223ac9c69e1c359fc648..bbdaaf7022b62d84594a29f1b60144920903a99a 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -277,6 +277,7 @@ static int __drm_connector_init(struct drm_device *dev, > INIT_LIST_HEAD(&connector->probed_modes); > INIT_LIST_HEAD(&connector->modes); > mutex_init(&connector->mutex); > + mutex_init(&connector->eld_mutex); > mutex_init(&connector->edid_override_mutex); > mutex_init(&connector->hdmi.infoframes.lock); > connector->edid_blob_ptr = NULL; > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 855beafb76ffbecf5c08d58e2f54bfb76f30b930..f0ca77bd42fd518d505d0db78557e0c8d83efb29 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -5657,6 +5657,8 @@ static void drm_edid_to_eld(struct drm_connector *connector, > if (!drm_edid) > return; > > + mutex_lock(&connector->eld_mutex); > + > mnl = get_monitor_name(drm_edid, &eld[DRM_ELD_MONITOR_NAME_STRING]); > drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] ELD monitor %s\n", > connector->base.id, connector->name, > @@ -5717,6 +5719,8 @@ static void drm_edid_to_eld(struct drm_connector *connector, > drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] ELD size %d, SAD count %d\n", > connector->base.id, connector->name, > drm_eld_size(eld), total_sad_count); > + > + mutex_unlock(&connector->eld_mutex); > } > > static int _drm_edid_to_sad(const struct drm_edid *drm_edid, > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > index e3fa43291f449d70f3b92a00985336c4f2237bc6..1e2b25e204cb523d61d30f5409faa059bf2b86eb 100644 > --- a/include/drm/drm_connector.h > +++ b/include/drm/drm_connector.h > @@ -2001,8 +2001,11 @@ struct drm_connector { > struct drm_encoder *encoder; > > #define MAX_ELD_BYTES 128 > - /** @eld: EDID-like data, if present */ > + /** @eld: EDID-like data, if present, protected by @eld_mutex */ > uint8_t eld[MAX_ELD_BYTES]; > + /** @eld_mutex: protection for concurrenct access to @eld */ > + struct mutex eld_mutex; > + > /** @latency_present: AV delay info from ELD, if found */ > bool latency_present[2]; > /** -- Jani Nikula, Intel