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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BEC23C77B72 for ; Mon, 17 Apr 2023 10:32:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230391AbjDQKcm (ORCPT ); Mon, 17 Apr 2023 06:32:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229682AbjDQKcj (ORCPT ); Mon, 17 Apr 2023 06:32:39 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1778810D for ; Mon, 17 Apr 2023 03:31:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1681727509; x=1713263509; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=R9ZDjMQbJbktdyenH5QRHh9b8IZO5KHOnPqhpyxlJ1s=; b=QT7trZ105xLudMr204vHs0Vn7tGb9c+Jgnlgtt606eNKk7DCtSSvw8be Q8OBsvlTJnZGdtwVZ25YD/VbPQ6A0ED0D1Ariaw2BrVHx0o2nauoDOa8S Yo//3MO1o/RjRBZ4tILX4s2/SalIv0OQqXaBN/Ww51X5Tx5wJRNFS7Js6 jecFTu95+saGUPPTj2zePUSspRlaQnQWe6Z4mtZN9BkgCeJXgog65mQoL MKAKtXJt6DI6ENFXV0NOYxATnQX1BivMZU2imx0mwiugpuWCdSAPoEbiP cv0zmxi1Gc1VDk4iyOrjMgjQs6pinNDyLrRfyE0gAmvUuLS0GLVitMZV9 g==; X-IronPort-AV: E=McAfee;i="6600,9927,10682"; a="347597320" X-IronPort-AV: E=Sophos;i="5.99,203,1677571200"; d="scan'208";a="347597320" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Apr 2023 03:29:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10682"; a="802064100" X-IronPort-AV: E=Sophos;i="5.99,203,1677571200"; d="scan'208";a="802064100" Received: from habramov-mobl4.ger.corp.intel.com (HELO localhost) ([10.252.47.83]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Apr 2023 03:29:54 -0700 From: Jani Nikula To: Jeff Layton , Lyude Paul , "Lin, Wayne" , Alex Deucher Cc: David Airlie , Daniel Vetter , "Deucher, Alexander" , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" Subject: Re: [PATCH] drm: make drm_dp_add_payload_part2 gracefully handle NULL state pointer In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20230413111254.22458-1-jlayton@kernel.org> <87edooarpq.fsf@intel.com> <4d8479f20ef30866fcf73f3602f1237376110764.camel@kernel.org> <878reug394.fsf@intel.com> <7a1b00f02b125bd65824b18ea09509efe3cf777d.camel@redhat.com> <874jpegao0.fsf@intel.com> Date: Mon, 17 Apr 2023 13:29:51 +0300 Message-ID: <87leiqer8g.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 17 Apr 2023, Jeff Layton wrote: > On Mon, 2023-04-17 at 11:44 +0300, Jani Nikula wrote: >> On Fri, 14 Apr 2023, Lyude Paul wrote: >> > On Fri, 2023-04-14 at 13:35 +0300, Jani Nikula wrote: >> > > On Fri, 14 Apr 2023, Jeff Layton wrote: >> > > > On Fri, 2023-04-14 at 04:40 +0000, Lin, Wayne wrote: >> > > > > [Public] >> > > > > >> > > > > Hi Jeff, >> > > > > >> > > > > Thanks. I might need more information to understand why we can't retrieve >> > > > > the drm atomic state. Also , "Failed to create MST payload for port" indicates >> > > > > error while configuring DPCD payload ID table. Could you help to provide log >> > > > > with KMS + ATOMIC + DP debug on please? Thanks in advance! >> > > > > >> > > > > Regards, >> > > > > Wayne >> > > > > >> > > > >> > > > Possibly. I'm not that familiar with display driver debugging. Can you >> > > > send me some directions on how to crank up that sort of debug logging? >> > > > >> > > > Note that this problem is _very_ intermittent too: I went about 2 weeks >> > > > between crashes, and then I got 3 in one day. I'd rather not run with a >> > > > lot of debug logging for a long time if that's what this is going to >> > > > require, as this is my main workstation. >> > > > >> > > > The last time I got this log message, my proposed patch did prevent the >> > > > box from oopsing, so I'd really like to see it go in unless it's just >> > > > categorically wrong for the caller to pass down a NULL state pointer to >> > > > drm_dp_add_payload_part2. >> > > >> > > Cc: Lyude. >> > > >> > > Looks like the state parameter was added in commit 4d07b0bc4034 >> > > ("drm/display/dp_mst: Move all payload info into the atomic state") and >> > > its only use is to get at state->dev for debug logging. >> > > >> > > What's the plan for the parameter? Surely something more than that! :) >> > >> > I don't think there was any plan for that, or at least I certainly don't even >> > remember adding that D:. It must totally have been by mistake and snuck by >> > review, if that's the only thing that we're using it for I'd say it's >> > definitely fine to just drop it entirely >> >> I guess we could use two patches then, first replace state->dev with >> mgr->dev as something that can be backported as needed, and second drop >> the state parameter altogether. >> >> Jeff, up for it? At least the first one? >> >> >> BR, >> Jani. >> > > Sure. I'm happy to test patches if you send them along. I was hoping to lure you into sending patches. ;) Anyway, I'm not working on this. BR, Jani. > > Thanks, -- Jani Nikula, Intel Open Source Graphics Center