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 6E1D3C433EF for ; Wed, 22 Dec 2021 15:38:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9319710E14C; Wed, 22 Dec 2021 15:38:43 +0000 (UTC) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id BE42C10E14C for ; Wed, 22 Dec 2021 15:38:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1640187522; x=1671723522; h=date:from:to:subject:message-id:references:mime-version: content-transfer-encoding:in-reply-to; bh=QLxH46RUV1e+aCttXsX7U9uT0kNXwDo8h1tUo+fVG8o=; b=oBSpHmx9xHymvc4mha6x7NmaoHvw1CNzDVwkwy1IadhxtaDGz82bNcp8 o6IRoIkmjBYdrzY3IoaazyYj2Aovy40F3LAfBwXNxrT8JU3rNAeRhsGx/ FepW1wCvRRqAdRoGlTNb1Hzga5SA9GqNJ10hxmtETEEaZIkTThThVKgFz 1j8P1BNo/9r8vaw0UjXVrGqHyoqVhM1qy6aMmwbKecTqOAaYx7dou5gE6 9RBMEn44MOEJ3xI2/7HIO1uR3jzvK9crx9m3nXMwFYbcs87nn8NQnYlfZ nm6vxnHOJyGkLVeEGarg8PKCPv5O2+Da44KfiBkPBwxaz0dFyhXbik+Bx A==; X-IronPort-AV: E=McAfee;i="6200,9189,10205"; a="220656340" X-IronPort-AV: E=Sophos;i="5.88,226,1635231600"; d="scan'208";a="220656340" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Dec 2021 07:38:42 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,226,1635231600"; d="scan'208";a="468210850" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.147]) by orsmga006.jf.intel.com with SMTP; 22 Dec 2021 07:38:40 -0800 Received: by stinkbox (sSMTP sendmail emulation); Wed, 22 Dec 2021 17:38:39 +0200 Date: Wed, 22 Dec 2021 17:38:39 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: intel-gfx@lists.freedesktop.org Message-ID: References: <20211217155403.31477-1-ville.syrjala@linux.intel.com> <20211217155403.31477-7-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: <20211217155403.31477-7-ville.syrjala@linux.intel.com> X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH 6/6] drm/i915/hdmi: Ignore DP++ TMDS clock limit for native HDMI ports 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Fri, Dec 17, 2021 at 05:54:03PM +0200, Ville Syrjala wrote: > From: Ville Syrjälä > > Lots of machines these days seem to have a crappy type1 DP dual > mode adaptor chip slapped onto the motherboard. Based on the > DP dual mode spec we currently limit those to 165MHz max TMDS > clock. > > Windows OTOH ignores DP dual mode adaptors when the VBT > indicates that the port is not actually DP++, so we can > perhaps assume that the vendors did intend that the 165MHz > clock limit doesn't apply here. Though it would be much > nicer if they actually declared an explicit limit through > VBT, but that doesn't seem to be happening either. > > So in order to match Windows behaviour let's ignore the > DP dual mode adaptor's TMDS clock limit for ports that > don't look like DP++ in VBT. > > Unfortunately many older VBTs misdelcare their DP++ ports > as just HDMI (eg. ILK Dell Latitude E5410) or DP (eg. SNB > Lenovo ThinkPad X220). So we can't really do this universally > without risking black screens. I suppose a sensible cutoff > is HSW+ since that's when 4k became a thing and one might > assume that the machines have been tested to work with higher > TMDS clock rates. > > Signed-off-by: Ville Syrjälä > --- > drivers/gpu/drm/i915/display/intel_hdmi.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c > index 3b5b9e7b05b7..9f0557d9e9a5 100644 > --- a/drivers/gpu/drm/i915/display/intel_hdmi.c > +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c > @@ -2359,6 +2359,14 @@ intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector, bool has_edid) > "DP dual mode adaptor (%s) detected (max TMDS clock: %d kHz)\n", > drm_dp_get_dual_mode_type_name(type), > hdmi->dp_dual_mode.max_tmds_clock); > + > + /* Older VBTs are often buggy and can't be trusted :( Play it safe. */ > + if ((DISPLAY_VER(dev_priv) >= 8 || IS_BROADWELL(dev_priv)) && As stated in the commit message I actually meant to say IS_HASWELL here, not IS_BROADWELL. > + !intel_bios_is_port_dp_dual_mode(dev_priv, port)) { > + drm_dbg_kms(&dev_priv->drm, > + "Ignoring DP dual mode adaptor max TMDS clock for native HDMI port\n"); > + hdmi->dp_dual_mode.max_tmds_clock = 0; > + } > } > > static bool > -- > 2.32.0 -- Ville Syrjälä Intel