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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 72129C43331 for ; Fri, 27 Mar 2020 15:40:47 +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 4C0F220936 for ; Fri, 27 Mar 2020 15:40:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C0F220936 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 876666EA4A; Fri, 27 Mar 2020 15:40:46 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id A71476EA4A for ; Fri, 27 Mar 2020 15:40:45 +0000 (UTC) IronPort-SDR: NRIf9kQJ3iSpVJqZZoCFj1Bfw8v60f0yHnGcLA1zwPWadPeSQo5dHbnUdchwyCaH3iVS9L5KKh D5PwxyCGPswQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2020 08:40:45 -0700 IronPort-SDR: +IhfL1mnKV5lc5HwmmnI6DqdeND2BVqtxLSRUlpOTINupl8JkyOvXLAbTeqY0zDUT8VArYP2fF yh0Xv/DGWX2A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,313,1580803200"; d="scan'208";a="240991460" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by fmsmga008.fm.intel.com with SMTP; 27 Mar 2020 08:40:42 -0700 Received: by stinkbox (sSMTP sendmail emulation); Fri, 27 Mar 2020 17:40:41 +0200 Date: Fri, 27 Mar 2020 17:40:41 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Manasi Navare Message-ID: <20200327154041.GG13686@intel.com> References: <20200319163844.22783-1-ville.syrjala@linux.intel.com> <20200319222049.GB11219@intel.com> <20200320190831.GQ13686@intel.com> <20200320231727.GD15035@intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200320231727.GD15035@intel.com> X-Patchwork-Hint: comment User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [Intel-gfx] [PATCH 1/3] drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure 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: Matteo Iervasi , Jani Nikula , Albert Astals Cid , intel-gfx@lists.freedesktop.org, Emanuele Panigati 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 Fri, Mar 20, 2020 at 04:17:27PM -0700, Manasi Navare wrote: > On Fri, Mar 20, 2020 at 09:08:31PM +0200, Ville Syrj=E4l=E4 wrote: > > On Thu, Mar 19, 2020 at 03:20:50PM -0700, Manasi Navare wrote: > > > On Thu, Mar 19, 2020 at 06:38:42PM +0200, Ville Syrjala wrote: > > > > From: Ville Syrj=E4l=E4 > > > > = > > > > Some new eDP panels don't like to operate at the max parameters, and > > > > instead we need to go for an optimal confiugration. That unfortunat= ely > > > > doesn't work with older eDP panels which are generally only guarant= eed > > > > to work at the max parameters. > > > > = > > > > To solve these two conflicting requirements let's start with the op= timal > > > > setup, and if that fails we start again with the max parameters. The > > > > downside is probably an extra modeset when we switch strategies but > > > > I don't see a good way to avoid that. > > > > = > > > > For a bit of history we first tried to go for the fast+narrow in > > > > commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config > > > > fast and narrow"). but that had to be reverted due to regression > > > > on older panels in commit f11cb1c19ad0 ("drm/i915/dp: revert back > > > > to max link rate and lane count on eDP"). So now we try to get > > > > the best of both worlds by using both strategies. > > > > = > > > > v2: Deal with output_bpp and uapi vs. hw state split > > > > Reword some comments > > > > = > > > > Cc: Jani Nikula > > > > Cc: Rodrigo Vivi > > > > Cc: Manasi Navare > > > > Cc: Albert Astals Cid # v5.0 backport > > > > Cc: Emanuele Panigati # v5.0 backport > > > > Cc: Matteo Iervasi # v5.0 backport > > > > Cc: Timo Aaltonen > > > > References: https://bugs.freedesktop.org/show_bug.cgi?id=3D105267 > > > > References: https://bugs.freedesktop.org/show_bug.cgi?id=3D109959 > > > > References: https://gitlab.freedesktop.org/drm/intel/issues/272 > > > > Signed-off-by: Ville Syrj=E4l=E4 > > > = > > > This approach looks good to me to fallback to max parameters if > > > it fails the first time. > > > = > > > > --- > > > > .../drm/i915/display/intel_display_types.h | 1 + > > > > drivers/gpu/drm/i915/display/intel_dp.c | 74 +++++++++++++++= +--- > > > > 2 files changed, 66 insertions(+), 9 deletions(-) > > > > = > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/d= rivers/gpu/drm/i915/display/intel_display_types.h > > > > index 5e00e611f077..ffde0d4af23c 100644 > > > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h > > > > @@ -1258,6 +1258,7 @@ struct intel_dp { > > > > bool link_trained; > > > > bool has_audio; > > > > bool reset_link_params; > > > > + bool use_max_params; > > > > u8 dpcd[DP_RECEIVER_CAP_SIZE]; > > > > u8 psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE]; > > > > u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS]; > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/= drm/i915/display/intel_dp.c > > > > index ef2e06e292d5..85abcce492ca 100644 > > > > --- a/drivers/gpu/drm/i915/display/intel_dp.c > > > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > > > > @@ -465,6 +465,12 @@ int intel_dp_get_link_train_fallback_values(st= ruct intel_dp *intel_dp, > > > > { > > > > int index; > > > > = > > > > + if (intel_dp_is_edp(intel_dp) && !intel_dp->use_max_params) { > > > > + DRM_DEBUG_KMS("Retrying Link training for eDP with max parameter= s\n"); > > > > + intel_dp->use_max_params =3D true; > > > > + return 0; > > > > + } > > > = > > > We need to remove the current check for intel_dp_can_link_train_fallb= ack_for_edp() right? > > = > > No. Why do you think it needs to be removed? > > > = > Okay so if trying max params link training again fails on eDP, then it fa= llsback from max to lower values > and fallback link training continues until it can handle the fixed mode w= ith the params or > the lowest params? > = > So if I understand it correctly we first try to use the optimum approach,= if that fails then > we try with max params so in this iteration if it fails again then max pa= rams is still true > then it will fallback and call intel_dp_can_link_train_fallback_for_edp()= and then > again keep retrying? Yep. -- = Ville Syrj=E4l=E4 Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx