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 4E158C3600B for ; Thu, 27 Mar 2025 07:36:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B607B10E08B; Thu, 27 Mar 2025 07:36:03 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="YUp2PcTJ"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1FEF710E08B for ; Thu, 27 Mar 2025 07:36:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1743060962; x=1774596962; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=yrY8VfjNeosBxXXkOauKnIhZOnR93pLSzmdIVaLmK3o=; b=YUp2PcTJRlL40XbEeeH6NlaAoKNl5WaILSx+S2vMJf3WaX3mGSfwCxO1 259QjtbWJUcnRIV/8dHrZQ44NOc0ohRllhBhyjdH/wRveOeajJJbSWkQg Wr9p32M2Jn029J0FpMAdVLEycFuGfcrDey115Or6Nt3fiQxhWq0Z2gKjR ij57rzTHaAuxQSrDL3U9xQ0z/gUUWSfbf1PUMq35p3zYRxR/FgFkhb2qh kILmcBNo9hvYHqMW9r16pMGoQO9QVJsZc8fcgeSThmd03WkwjZWQ5Whyb 7lRZm/xMh4oSWVw2hvjBgKhG6T0zDZ2LgogmsJE14RYdT9aoCFGtGUH1S g==; X-CSE-ConnectionGUID: hLPZ2Dj2Qjyi3h4S35ma/Q== X-CSE-MsgGUID: vTEOCE0KRLSfu2sofhUNWA== X-IronPort-AV: E=McAfee;i="6700,10204,11385"; a="44297071" X-IronPort-AV: E=Sophos;i="6.14,279,1736841600"; d="scan'208";a="44297071" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2025 00:36:01 -0700 X-CSE-ConnectionGUID: rvqhyw/1TaqgLYess/peMw== X-CSE-MsgGUID: 7pjgDcxfTh+aro5gLqyw8w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.14,279,1736841600"; d="scan'208";a="125029781" Received: from ncintean-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.246.17]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Mar 2025 00:35:59 -0700 From: Jani Nikula To: Ville Syrjala , intel-gfx@lists.freedesktop.org Cc: stable@vger.kernel.org Subject: Re: [PATCH v2 1/2] drm/i915/dp: Reject HBR3 when sink doesn't support TPS4 In-Reply-To: <20250306210740.11886-1-ville.syrjala@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20250303123952.5669-1-ville.syrjala@linux.intel.com> <20250306210740.11886-1-ville.syrjala@linux.intel.com> Date: Thu, 27 Mar 2025 09:35:56 +0200 Message-ID: <87h63f6i3n.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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 Thu, 06 Mar 2025, Ville Syrjala wrote: > From: Ville Syrj=C3=A4l=C3=A4 > > According to the DP spec TPS4 is mandatory for HBR3. We have > however seen some broken eDP sinks that violate this and > declare support for HBR3 without TPS4 support. > > At least in the case of the icl Dell XPS 13 7390 this results > in an unstable output. > > Reject HBR3 when TPS4 supports is unavailable on the sink. > > v2: Leave breadcrumbs in dmesg to avoid head scratching (Jani) > > Cc: stable@vger.kernel.org > Cc: Jani Nikula > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/5969 > Signed-off-by: Ville Syrj=C3=A4l=C3=A4 Reviewed-by: Jani Nikula > --- > drivers/gpu/drm/i915/display/intel_dp.c | 49 +++++++++++++++++++++---- > 1 file changed, 42 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i9= 15/display/intel_dp.c > index 205ec315b413..70f5d1465f81 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -172,10 +172,28 @@ int intel_dp_link_symbol_clock(int rate) >=20=20 > static int max_dprx_rate(struct intel_dp *intel_dp) > { > + struct intel_display *display =3D to_intel_display(intel_dp); > + struct intel_encoder *encoder =3D &dp_to_dig_port(intel_dp)->base; > + int max_rate; > + > if (intel_dp_tunnel_bw_alloc_is_enabled(intel_dp)) > - return drm_dp_tunnel_max_dprx_rate(intel_dp->tunnel); > + max_rate =3D drm_dp_tunnel_max_dprx_rate(intel_dp->tunnel); > + else > + max_rate =3D drm_dp_bw_code_to_link_rate(intel_dp->dpcd[DP_MAX_LINK_RA= TE]); >=20=20 > - return drm_dp_bw_code_to_link_rate(intel_dp->dpcd[DP_MAX_LINK_RATE]); > + /* > + * Some broken eDP sinks illegally declare support for > + * HBR3 without TPS4, and are unable to produce a stable > + * output. Reject HBR3 when TPS4 is not available. > + */ > + if (max_rate >=3D 810000 && !drm_dp_tps4_supported(intel_dp->dpcd)) { > + drm_dbg_kms(display->drm, > + "[ENCODER:%d:%s] Rejecting HBR3 due to missing TPS4 support\n", > + encoder->base.base.id, encoder->base.name); > + max_rate =3D 540000; > + } > + > + return max_rate; > } >=20=20 > static int max_dprx_lane_count(struct intel_dp *intel_dp) > @@ -4170,6 +4188,9 @@ static void intel_edp_mso_init(struct intel_dp *int= el_dp) > static void > intel_edp_set_sink_rates(struct intel_dp *intel_dp) > { > + struct intel_display *display =3D to_intel_display(intel_dp); > + struct intel_encoder *encoder =3D &dp_to_dig_port(intel_dp)->base; > + > intel_dp->num_sink_rates =3D 0; >=20=20 > if (intel_dp->edp_dpcd[0] >=3D DP_EDP_14) { > @@ -4180,10 +4201,7 @@ intel_edp_set_sink_rates(struct intel_dp *intel_dp) > sink_rates, sizeof(sink_rates)); >=20=20 > for (i =3D 0; i < ARRAY_SIZE(sink_rates); i++) { > - int val =3D le16_to_cpu(sink_rates[i]); > - > - if (val =3D=3D 0) > - break; > + int rate; >=20=20 > /* Value read multiplied by 200kHz gives the per-lane > * link rate in kHz. The source rates are, however, > @@ -4191,7 +4209,24 @@ intel_edp_set_sink_rates(struct intel_dp *intel_dp) > * back to symbols is > * (val * 200kHz)*(8/10 ch. encoding)*(1/8 bit to Byte) > */ > - intel_dp->sink_rates[i] =3D (val * 200) / 10; > + rate =3D le16_to_cpu(sink_rates[i]) * 200 / 10; > + > + if (rate =3D=3D 0) > + break; > + > + /* > + * Some broken eDP sinks illegally declare support for > + * HBR3 without TPS4, and are unable to produce a stable > + * output. Reject HBR3 when TPS4 is not available. > + */ > + if (rate >=3D 810000 && !drm_dp_tps4_supported(intel_dp->dpcd)) { > + drm_dbg_kms(display->drm, > + "[ENCODER:%d:%s] Rejecting HBR3 due to missing TPS4 support\n", > + encoder->base.base.id, encoder->base.name); > + break; > + } > + > + intel_dp->sink_rates[i] =3D rate; > } > intel_dp->num_sink_rates =3D i; > } --=20 Jani Nikula, Intel