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 X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59E77C433FE for ; Thu, 16 Sep 2021 16:25:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3ADA26103B for ; Thu, 16 Sep 2021 16:25:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241347AbhIPQ1K (ORCPT ); Thu, 16 Sep 2021 12:27:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:37482 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240819AbhIPQZL (ORCPT ); Thu, 16 Sep 2021 12:25:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id AA588613CE; Thu, 16 Sep 2021 16:16:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631808991; bh=vHuqIDHvWxPgaCQEKm/V2kYjdfojuwWIISJ9PRqTjFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z0fU1XPq6WRZPtSnIT7tDo6sKrHgP6hWwxKqiiFFhajLBeDQPkqGd/Hr/4YnoMPAl RKhtrPJYnpDu2iLKVfAk5oW0JdJCgRA+PGjsciX9netAVnWQ43stVn4tnBIct7GkhW YwTmFwwnd+uN52U+uWoWxILtSNzWwPWyKv7sNbhM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rajkumar Subbiah , Kuogee Hsieh , Stephen Boyd , Jani Nikula , Lyude Paul Subject: [PATCH 5.10 298/306] drm/dp_mst: Fix return code on sideband message failure Date: Thu, 16 Sep 2021 18:00:43 +0200 Message-Id: <20210916155804.251002646@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210916155753.903069397@linuxfoundation.org> References: <20210916155753.903069397@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Rajkumar Subbiah commit 92bd92c44d0d9be5dcbcda315b4be4b909ed9740 upstream. Commit 2f015ec6eab6 ("drm/dp_mst: Add sideband down request tracing + selftests") added some debug code for sideband message tracing. But it seems to have unintentionally changed the behavior on sideband message failure. It catches and returns failure only if DRM_UT_DP is enabled. Otherwise it ignores the error code and returns success. So on an MST unplug, the caller is unaware that the clear payload message failed and ends up waiting for 4 seconds for the response. Fixes the issue by returning the proper error code. Changes in V2: -- Revise commit text as review comment -- add Fixes text Changes in V3: -- remove "unlikely" optimization Fixes: 2f015ec6eab6 ("drm/dp_mst: Add sideband down request tracing + selftests") Cc: # v5.5+ Signed-off-by: Rajkumar Subbiah Signed-off-by: Kuogee Hsieh Reviewed-by: Stephen Boyd Reviewed-by: Jani Nikula Reviewed-by: Lyude Paul Signed-off-by: Lyude Paul Link: https://patchwork.freedesktop.org/patch/msgid/1625585434-9562-1-git-send-email-khsieh@codeaurora.org Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2869,11 +2869,13 @@ static int process_single_tx_qlock(struc idx += tosend + 1; ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx); - if (unlikely(ret) && drm_debug_enabled(DRM_UT_DP)) { - struct drm_printer p = drm_debug_printer(DBG_PREFIX); + if (ret) { + if (drm_debug_enabled(DRM_UT_DP)) { + struct drm_printer p = drm_debug_printer(DBG_PREFIX); - drm_printf(&p, "sideband msg failed to send\n"); - drm_dp_mst_dump_sideband_msg_tx(&p, txmsg); + drm_printf(&p, "sideband msg failed to send\n"); + drm_dp_mst_dump_sideband_msg_tx(&p, txmsg); + } return ret; }