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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 DAC30C433DB for ; Wed, 24 Mar 2021 14:03:02 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9080161A07 for ; Wed, 24 Mar 2021 14:03:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9080161A07 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 190F36E9D4; Wed, 24 Mar 2021 14:02:59 +0000 (UTC) Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1E3476E9D4; Wed, 24 Mar 2021 14:02:57 +0000 (UTC) IronPort-SDR: eoVd/ucKh54023d3PuxhjFyiM8L7mmFqeexTC7n9BRZUcgcPvCXRjPUxeoacn+ADfII1zAImYS ThPHePsEyOwg== X-IronPort-AV: E=McAfee;i="6000,8403,9932"; a="177824816" X-IronPort-AV: E=Sophos;i="5.81,274,1610438400"; d="scan'208";a="177824816" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Mar 2021 07:02:55 -0700 IronPort-SDR: Lv+37aIFxUOXRI8IuHITv5PQulAuCboftcDEkGkPzbJ8oO+O10ZwqN/XQHz+T+68jS0cGIF/ch d+ySLTW+oAXg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,274,1610438400"; d="scan'208";a="408855419" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.171]) by fmsmga008.fm.intel.com with SMTP; 24 Mar 2021 07:02:53 -0700 Received: by stinkbox (sSMTP sendmail emulation); Wed, 24 Mar 2021 16:02:52 +0200 Date: Wed, 24 Mar 2021 16:02:52 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Hans de Goede Message-ID: References: <20210302120040.94435-1-hdegoede@redhat.com> <20210302120040.94435-3-hdegoede@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH resend 2/2] drm/i915/display: Make vlv_find_free_pps() skip pipes which are in use for non DP purposes 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 , dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Mar 23, 2021 at 11:39:09AM +0100, Hans de Goede wrote: > Hi, > = > On 3/2/21 3:51 PM, Ville Syrj=E4l=E4 wrote: > > On Tue, Mar 02, 2021 at 01:00:40PM +0100, Hans de Goede wrote: > >> As explained by a long comment block, on VLV intel_setup_outputs() > >> sometimes thinks there might be an eDP panel connected while there is = none. > >> In this case intel_setup_outputs() will call intel_dp_init() to check. > >> > >> In this scenario vlv_find_free_pps() ends up selecting pipe A for the = pps, > >> even though this might be in use for non DP purposes. When this is the= case > >> then the assert_pipe() in vlv_force_pll_on() will fail when called from > >> vlv_power_sequencer_kick(). > > = > > The idea is that you *can* select a PPS from a pipe used for a non-DP > > port since those don't care about the PPS stuff. So this doesn't seem > > correct. > = > They may not care about the PPS stuff, but as the WARN / backtrace > shows if the DPLL_VCO_ENABLE bit is not already set for the pipe, while > the pipe is "otherwise" in use then vlv_force_pll_on() becomes unhappy > triggering the WARN. > = > > a) I would like to see the VBT for this machine > = > https://fedorapeople.org/~jwrdegoede/voyo-winpad-a15-vbt > = > > b) I wonder if the DSI PLL is sufficient for getting the PPS going? > = > I have no idea, I just noticed the WARN / backtrace and this seemed > like a reasonably way to deal with it. With that said I'm fine with fixing > this a different way. > = > > c) If we do need the normal DPLL is there any harm to DSI in enabling i= t? > = > I would assume this increases power-consumption and DSI panels are almost > always used in battery powered devices. This is just used while probing the panel, so power consumption is not a concern. > = > Also this would impact all BYT/CHT devices, possible triggering unwanted > side-effects. Where as the proposed fix below is much more narrowly targe= ted > at the problem. It might not be the most pretty fix but AFAICT it has a l= ow > risk of causing regressions. It rather significantly changes the logic of the workaround, potentially causing us to not find a free PPS at all. Eg. if you were to boot with a VLV with pipe A -> eDP B + eDP C inactive + pipe B -> VGA then your change would cause us to not find the free pipe B PPS for probing eDP C, and in the end we'd get a WARN and fall back to pipe A PPS which would clobber the actually in use pipe A PPS. -- = Ville Syrj=E4l=E4 Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx