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 B62C6C64EC4 for ; Wed, 8 Mar 2023 22:25:25 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3441B10E747; Wed, 8 Mar 2023 22:25:25 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id B096810E747 for ; Wed, 8 Mar 2023 22:25:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678314323; x=1709850323; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=5P3jWskLiVSoI9CvbNKdvWS237A5AQC2xy13XKxDo5U=; b=FpC24wPLh7UlHSjnKxU2y6b2DTlRrkgzbwn+8Dx4x2s109KENPF8TsA3 6CUxajqZWFGkHwGYoSj9CChk7WO0oCOkAl7P9uqKCdS8PLpOri9q743o1 XwRPyqSEdQSSNZ1M4pVwwyjZRT7w8o6VESwOLojtYvS/njiz8ec3QR7o7 WDOqPZa85ZMHwmj9AT1PQ0qpa2lKG6uG06Zzct+ZwpaFA7lODIdl8GUzf 6no46VnDwi3x5gwYEhCbIjNrFWN0ptvMLx9pI1RP0HPtkVsnpyPdD23u2 IK+eNgRgzj7p6SHhZM+BS8pSYBokgq5QSxsR/SglqTktQOptSAtWvTbN2 g==; X-IronPort-AV: E=McAfee;i="6500,9779,10643"; a="401121509" X-IronPort-AV: E=Sophos;i="5.98,244,1673942400"; d="scan'208";a="401121509" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2023 14:25:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10643"; a="670496838" X-IronPort-AV: E=Sophos;i="5.98,244,1673942400"; d="scan'208";a="670496838" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.70]) by orsmga007.jf.intel.com with SMTP; 08 Mar 2023 14:25:09 -0800 Received: by stinkbox (sSMTP sendmail emulation); Thu, 09 Mar 2023 00:25:08 +0200 Date: Thu, 9 Mar 2023 00:25:08 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Imre Deak Message-ID: References: <20230214134348.11020-1-ville.syrjala@linux.intel.com> <20230214134348.11020-3-ville.syrjala@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH 3/3] drm/i915: Fix idle pattern enabling X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Mar 09, 2023 at 12:19:09AM +0200, Imre Deak wrote: > On Wed, Mar 08, 2023 at 11:28:07PM +0200, Ville Syrjälä wrote: > > On Thu, Mar 02, 2023 at 09:03:42PM +0200, Imre Deak wrote: > > > On Tue, Feb 14, 2023 at 03:43:48PM +0200, Ville Syrjala wrote: > > > > From: Ville Syrjälä > > > > > > > > Currently we are always switching to the idle pattern after the > > > > link training, but we don't always wait for the minimum number > > > > of idle patterns sent. That doesn't look to be what Bspec > > > > asks of us. > > > > > > > > According to bspec what we should do is switch to idle pattern > > > > and wait for it only in DP1.4 MST cases. In all other cases we > > > > should apparently do neither. > > > > > > > > What confuses matters further is that the port sync SST sequence > > > > asks us to "stay in idle pattern". But if we never switched to it > > > > how can we stay in it? This still needs further clarificaiton. > > > > > > HSW seems to require it also for SST, but yes for all other platforms > > > bspec only requires it for MST. > > > > commit 3ab9c63705cb ("drm/i915: hsw: fix link training for eDP on > > port-A") (written by you it seems :) says there was some problem on > > HSW that needed it for DDI A SST as well. But it's not really obvious > > why you skipped the IDLE_DONE thing there. Maybe just an optimization? > > Ok, forgot about that. Looking back at the discussion the problem on HSW > was that switching from sending idle patterns to normal mode didn't > happen automatically due to some HW problem. The workaround was to to > switch to idle patterns and enable normal mode manually after the pipe > is enabled. The WA didn't require waiting for IDLE_DONE, but before > TGL there is no DP_TP_STATUS register on port A either. Ah, that would explain it. Also might explain some hardcoded wait values I saw in some GOP stuff. -- Ville Syrjälä Intel