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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 18535C07E98 for ; Mon, 5 Jul 2021 09:07:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA22761260 for ; Mon, 5 Jul 2021 09:07:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230301AbhGEJKY (ORCPT ); Mon, 5 Jul 2021 05:10:24 -0400 Received: from mga05.intel.com ([192.55.52.43]:41923 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230121AbhGEJKX (ORCPT ); Mon, 5 Jul 2021 05:10:23 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10035"; a="294590796" X-IronPort-AV: E=Sophos;i="5.83,325,1616482800"; d="scan'208";a="294590796" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2021 02:07:46 -0700 X-IronPort-AV: E=Sophos;i="5.83,325,1616482800"; d="scan'208";a="485435002" Received: from elang-mobl.ger.corp.intel.com (HELO localhost) ([10.252.59.138]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2021 02:07:41 -0700 From: Jani Nikula To: Kuogee Hsieh , robdclark@gmail.com, sean@poorly.run, swboyd@chromium.org, lyude@redhat.com Cc: rnayak@codeaurora.org, tzimmermann@suse.de, airlied@linux.ie, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, abhinavk@codeaurora.org, khsieh@codeaurora.org, aravindh@codeaurora.org, freedreno@lists.freedesktop.org, rsubbia@codeaurora.org Subject: Re: [PATCH v2] drm/dp_mst: Fix return code on sideband message failure In-Reply-To: <1625008068-16458-1-git-send-email-khsieh@codeaurora.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <1625008068-16458-1-git-send-email-khsieh@codeaurora.org> Date: Mon, 05 Jul 2021 12:07:38 +0300 Message-ID: <87czrx9lid.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 29 Jun 2021, Kuogee Hsieh wrote: > From: Rajkumar Subbiah > > 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 > > Fixes: 2f015ec6eab6 ("drm/dp_mst: Add sideband down request tracing + selftests") > > Signed-off-by: Rajkumar Subbiah > Signed-off-by: Kuogee Hsieh > > Reviewed-by: Stephen Boyd > --- > drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c > index 1590144..8d97430 100644 > --- a/drivers/gpu/drm/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c > @@ -2887,11 +2887,13 @@ static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr, > 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 (unlikely(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; > } Seems like a sensible thing to do. (I'd probably rip out the "unlikely" while at it, as it feels like unnecessary optimization, but *shrug*.) Reviewed-by: Jani Nikula -- Jani Nikula, Intel Open Source Graphics Center