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=unavailable 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 BB15DC433DF for ; Tue, 7 Jul 2020 23:12:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C497206BE for ; Tue, 7 Jul 2020 23:12:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728592AbgGGXMj (ORCPT ); Tue, 7 Jul 2020 19:12:39 -0400 Received: from mga01.intel.com ([192.55.52.88]:27798 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727777AbgGGXMi (ORCPT ); Tue, 7 Jul 2020 19:12:38 -0400 IronPort-SDR: 5DYJ162OmQuognN5N60v/ipe1MbTzto7nYYWo0Yo5aDx3mYU75HWzo2gcQ6a3jMbG05Uo4xC0c gj3PwxtffiJg== X-IronPort-AV: E=McAfee;i="6000,8403,9675"; a="165783022" X-IronPort-AV: E=Sophos;i="5.75,325,1589266800"; d="scan'208";a="165783022" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2020 16:12:36 -0700 IronPort-SDR: BTtvrTuI7Rq/6kKI1tRiK0WsR/JhgkaBU0FlPiow27t0jKe11+R3Qyo1VIiwfgZxJLP4zTQsFV FnYJJDW1+gdg== X-IronPort-AV: E=Sophos;i="5.75,325,1589266800"; d="scan'208";a="427637462" Received: from ideak-desk.fi.intel.com ([10.237.72.183]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2020 16:12:34 -0700 Date: Wed, 8 Jul 2020 02:12:29 +0300 From: Imre Deak To: Lyude Paul Cc: dri-devel@lists.freedesktop.org, Cooper Chiou , David Airlie , intel-gfx@lists.freedesktop.org, Lucas De Marchi , linux-kernel@vger.kernel.org Subject: Re: [Intel-gfx] [PATCH 2/2] drm/i915/mst: filter out the display mode exceed sink's capability Message-ID: <20200707231229.GB22747@ideak-desk.fi.intel.com> Reply-To: imre.deak@intel.com References: <20200526182313.4005-1-lyude@redhat.com> <20200526182313.4005-3-lyude@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200526182313.4005-3-lyude@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 26, 2020 at 02:23:10PM -0400, Lyude Paul wrote: > From: Lee Shawn C > > So far, max dot clock rate for MST mode rely on physcial > bandwidth limitation. It would caused compatibility issue > if source display resolution exceed MST hub output ability. > > For example, source DUT had DP 1.2 output capability. > And MST docking just support HDMI 1.4 spec. When a HDMI 2.0 > monitor connected. Source would retrieve EDID from external > and get max resolution 4k@60fps. DP 1.2 can support 4K@60fps > because it did not surpass DP physical bandwidth limitation. > Do modeset to 4k@60fps, source output display data but MST > docking can't output HDMI properly due to this resolution > already over HDMI 1.4 spec. > > Refer to commit ("drm/dp_mst: Use full_pbn > instead of available_pbn for bandwidth checks"). > Source driver should refer to full_pbn to evaluate sink > output capability. And filter out the resolution surpass > sink output limitation. > > v2: Using mgr->base.lock to protect full_pbn. > v3: Add ctx lock. > v4: > * s/intel_dp_mst_mode_clock_exceed_pbn_bandwidth/ > intel_dp_mst_mode_clock_exceeds_pbn_bw/ > * Use the new drm_connector_helper_funcs.mode_valid_ctx to properly pipe > down the drm_modeset_acquire_ctx that the probe helpers are using, so > we can safely grab &mgr->base.lock without deadlocking > > Cc: Manasi Navare > Cc: Jani Nikula > Cc: Ville Syrjala > Cc: Cooper Chiou > Co-developed-by: Lyude Paul > Signed-off-by: Lee Shawn C > Tested-by: Lee Shawn C > Signed-off-by: Lyude Paul > --- > drivers/gpu/drm/i915/display/intel_dp_mst.c | 39 ++++++++++++++++++--- > 1 file changed, 35 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c > index d18b406f2a7d2..cf052095ad785 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c > @@ -610,15 +610,42 @@ static int intel_dp_mst_get_modes(struct drm_connector *connector) > return intel_dp_mst_get_ddc_modes(connector); > } > > +static int > +intel_dp_mst_mode_clock_exceeds_pbn_bw(struct drm_connector *connector, > + struct drm_modeset_acquire_ctx *ctx, > + int clock, int bpp) > +{ > + struct intel_connector *intel_connector = to_intel_connector(connector); > + struct intel_dp *intel_dp = intel_connector->mst_port; > + struct drm_dp_mst_topology_mgr *mgr = &intel_dp->mst_mgr; > + struct drm_dp_mst_port *port = (to_intel_connector(connector))->port; intel_connector > + int ret = MODE_OK; > + > + if (!mgr) As a NULL check this would be bogus, but also connector->mst_port and so mst_mgr too should be always non-NULL? > + return ret; > + > + ret = drm_modeset_lock(&mgr->base.lock, ctx); > + if (ret == -EDEADLK) > + return ret; > + > + if (port->full_pbn && How could full_pbn be unset? > + drm_dp_calc_pbn_mode(clock, bpp, false) > port->full_pbn) > + ret = MODE_CLOCK_HIGH; > + > + return ret; > +} > + > static enum drm_mode_status > -intel_dp_mst_mode_valid(struct drm_connector *connector, > - struct drm_display_mode *mode) > +intel_dp_mst_mode_valid_ctx(struct drm_connector *connector, > + struct drm_display_mode *mode, > + struct drm_modeset_acquire_ctx *ctx) > { > struct drm_i915_private *dev_priv = to_i915(connector->dev); > struct intel_connector *intel_connector = to_intel_connector(connector); > struct intel_dp *intel_dp = intel_connector->mst_port; > int max_dotclk = to_i915(connector->dev)->max_dotclk_freq; > int max_rate, mode_rate, max_lanes, max_link_clock; > + int ret; > > if (drm_connector_is_unregistered(connector)) > return MODE_ERROR; > @@ -632,7 +659,11 @@ intel_dp_mst_mode_valid(struct drm_connector *connector, > max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes); > mode_rate = intel_dp_link_required(mode->clock, 18); > > - /* TODO - validate mode against available PBN for link */ > + ret = intel_dp_mst_mode_clock_exceeds_pbn_bw(connector, ctx, > + mode->clock, 24); Why 24 bpp and not 18? Nit: could be checked after max_rate/max_dotclk for consistency. > + if (ret != MODE_OK) > + return ret; > + > if (mode->clock < 10000) > return MODE_CLOCK_LOW; > > @@ -671,7 +702,7 @@ intel_dp_mst_detect(struct drm_connector *connector, > > static const struct drm_connector_helper_funcs intel_dp_mst_connector_helper_funcs = { > .get_modes = intel_dp_mst_get_modes, > - .mode_valid = intel_dp_mst_mode_valid, > + .mode_valid_ctx = intel_dp_mst_mode_valid_ctx, > .atomic_best_encoder = intel_mst_atomic_best_encoder, > .atomic_check = intel_dp_mst_atomic_check, > .detect_ctx = intel_dp_mst_detect, > -- > 2.26.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx >