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 6F43ECD6E4A for ; Fri, 29 May 2026 14:58:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2B718112061; Fri, 29 May 2026 14:58:07 +0000 (UTC) Received: from exchange.fintech.ru (exchange.fintech.ru [195.54.195.159]) by gabe.freedesktop.org (Postfix) with ESMTPS id 57574112067; Fri, 29 May 2026 14:58:05 +0000 (UTC) Received: from Ex16-01.fintech.ru (10.0.10.18) by exchange.fintech.ru (195.54.195.169) with Microsoft SMTP Server (TLS) id 14.3.498.0; Fri, 29 May 2026 17:58:03 +0300 Received: from localhost (10.0.253.153) by Ex16-01.fintech.ru (10.0.10.18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2242.4; Fri, 29 May 2026 17:58:02 +0300 From: Nikita Zhandarovich To: Jani Nikula , Rodrigo Vivi , Joonas Lahtinen CC: Nikita Zhandarovich , Tvrtko Ursulin , David Airlie , Simona Vetter , , , , , Subject: [PATCH v2] drm/i915/edp: Check supported link rates DPCD read Date: Fri, 29 May 2026 17:57:58 +0300 Message-ID: <20260529145759.1640646-1-n.zhandarovich@fintech.ru> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.0.253.153] X-ClientProxiedBy: Ex16-02.fintech.ru (10.0.10.19) To Ex16-01.fintech.ru (10.0.10.18) 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" intel_edp_set_sink_rates() reads DP_SUPPORTED_LINK_RATES into a local stack array and then parses the array unconditionally. If the read fails, the array contents are not valid and may result in bogus sink link rates being used. Use drm_dp_dpcd_read_data() and clear the sink rate array on failure, so the existing parser falls back to the default sink rate handling. Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE. Fixes: 68f357cb7347 ("drm/i915/dp: generate and cache sink rate array for all DP, not just eDP 1.4") Signed-off-by: Nikita Zhandarovich --- v1 -> v2: - Use drm_dp_dpcd_read_data() instead of drm_dp_dpcd_read(). - Avoid the goto by clearing sink_rates on read failure, as suggested by Jani Nikula. - Adjust patch description. drivers/gpu/drm/i915/display/intel_dp.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 6ef2a0043cda..5c3e816b0135 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -4678,10 +4678,17 @@ intel_edp_set_sink_rates(struct intel_dp *intel_dp) if (intel_dp->edp_dpcd[0] >= DP_EDP_14) { __le16 sink_rates[DP_MAX_SUPPORTED_RATES]; + int ret; int i; - drm_dp_dpcd_read(&intel_dp->aux, DP_SUPPORTED_LINK_RATES, - sink_rates, sizeof(sink_rates)); + ret = drm_dp_dpcd_read_data(&intel_dp->aux, + DP_SUPPORTED_LINK_RATES, + sink_rates, sizeof(sink_rates)); + if (ret < 0) { + drm_dbg_kms(display->drm, + "Unable to read eDP supported link rates, using default rates\n"); + memset(sink_rates, 0, sizeof(sink_rates)); + } for (i = 0; i < ARRAY_SIZE(sink_rates); i++) { int rate;