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 B6610C8303C for ; Tue, 8 Jul 2025 15:26:48 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7498A10E137; Tue, 8 Jul 2025 15:26:48 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="blut8qn3"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id 15EE610E137; Tue, 8 Jul 2025 15:26:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1751988408; x=1783524408; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=4iV+WsB43o0lQdpXMRojwBPOtp66aR79FZRerRm2PG4=; b=blut8qn3dje5c0T349SG/hD2trQT5GW7/1DX5Dkg+KI32g9EvOx/fYYn vnZLlGVU5tigB1QQg6bxoBmMrm5sJJxl2tSZlSRSfK6wUghiPv1mQd9X3 JOrRRoFoDeuibjYdPkshF7JbfzoJ4nOOBoHhFgGHjn4O1i76a41aaa+Ix jnDpmdlwrjnfykJdKfNjeVjut9shHkx+l7nuVyzmsAR9OaSG/yCUWZ4Gm 3o4DThbiq4pJnJZ2jtuqahx3qkg3aSzDKFt7ecT8NhO5Txq49jxGqntfN xYfKMko4jXmjENMjGytBAY9A6Hd11u4QtX3Uyck7Tt+F5Wikc66OCHmZW g==; X-CSE-ConnectionGUID: dVkkC0tMRbKHMYxwpExCpw== X-CSE-MsgGUID: 1Rek7V2jRzCSVzHxWLSHWw== X-IronPort-AV: E=McAfee;i="6800,10657,11487"; a="54363341" X-IronPort-AV: E=Sophos;i="6.16,297,1744095600"; d="scan'208";a="54363341" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2025 08:26:47 -0700 X-CSE-ConnectionGUID: 8wsB15r0TYaGNI11WRDMEw== X-CSE-MsgGUID: JGfo1jxqSDiIGRpPLZVb5w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,297,1744095600"; d="scan'208";a="161170094" Received: from johunt-mobl9.ger.corp.intel.com (HELO stinkbox) ([10.245.245.55]) by orviesa005.jf.intel.com with SMTP; 08 Jul 2025 08:26:44 -0700 Received: by stinkbox (sSMTP sendmail emulation); Tue, 08 Jul 2025 18:26:42 +0300 Date: Tue, 8 Jul 2025 18:26:42 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: "Nautiyal, Ankit K" Cc: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, jani.nikula@linux.intel.com, stable@vger.kernel.org Subject: Re: [RESEND 1/1] drm/i915/dp: Refine TPS4-based HBR3 rejection and add quirk to limit eDP to HBR2 Message-ID: References: <20250627084059.2575794-2-ankit.k.nautiyal@intel.com> <20250706053149.3997091-1-ankit.k.nautiyal@intel.com> <094d5dba-3483-4133-99e8-9e32d42ba2f6@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <094d5dba-3483-4133-99e8-9e32d42ba2f6@intel.com> X-Patchwork-Hint: comment X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, Jul 08, 2025 at 08:43:37PM +0530, Nautiyal, Ankit K wrote: > > On 7/8/2025 7:44 PM, Ville Syrjälä wrote: > > On Sun, Jul 06, 2025 at 11:01:49AM +0530, Ankit Nautiyal wrote: > >> Refine the logic introduced in commit 584cf613c24a ("drm/i915/dp: Reject > >> HBR3 when sink doesn't support TPS4") to allow HBR3 on eDP panels that > >> report DPCD revision 1.4, even if TPS4 is not supported. This aligns with > >> the DisplayPort specification, which does not mandate TPS4 support for eDP > >> with DPCD rev 1.4. > >> > >> This change avoids regressions on panels that require HBR3 to operate at > >> their native resolution but do not advertise TPS4 support. > >> > >> Additionally, some ICL/TGL platforms with combo PHY ports suffer from > >> signal integrity issues at HBR3. While certain systems include a > >> Parade PS8461 mux to mitigate this, its presence cannot be reliably > >> detected. Furthermore, broken or missing VBT entries make it unsafe to > >> rely on VBT for enforcing link rate limits. > >> > >> To address the HBR3-related issues on such platforms and eDP panels, > >> introduce a device specific quirk to cap the eDP link rate to HBR2 > >> (540000 kHz). This will override any higher advertised rates from > >> the sink or DPCD for specific devices. > >> > >> Currently, the quirk is added for Dell XPS 13 7390 2-in-1 which is > >> reported in gitlab issue #5969 [1]. > >> > >> [1] https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/5969 > >> [2] https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14517 > >> > >> Fixes: 584cf613c24a ("drm/i915/dp: Reject HBR3 when sink doesn't support TPS4") > >> Cc: Jani Nikula > >> Cc: Ville Syrjälä > >> Cc: # v6.15+ > >> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/5969 > >> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14517 > >> Signed-off-by: Ankit Nautiyal > >> --- > >> drivers/gpu/drm/i915/display/intel_dp.c | 31 +++++++++++++++++++-- > >> drivers/gpu/drm/i915/display/intel_quirks.c | 9 ++++++ > >> drivers/gpu/drm/i915/display/intel_quirks.h | 1 + > >> 3 files changed, 39 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > >> index f48912f308df..362e376fca27 100644 > >> --- a/drivers/gpu/drm/i915/display/intel_dp.c > >> +++ b/drivers/gpu/drm/i915/display/intel_dp.c > >> @@ -171,6 +171,15 @@ int intel_dp_link_symbol_clock(int rate) > >> return DIV_ROUND_CLOSEST(rate * 10, intel_dp_link_symbol_size(rate)); > >> } > >> > >> +static bool intel_dp_reject_hbr3_due_to_tps4(struct intel_dp *intel_dp) > >> +{ > >> + /* TPS4 is not mandatory for eDP with DPCD rev 1.4 */ > >> + if (intel_dp_is_edp(intel_dp) && intel_dp->dpcd[DP_DPCD_REV] == 0x14) > >> + return false; > >> + > >> + return !drm_dp_tps4_supported(intel_dp->dpcd); > >> +} > > This feels like it's getty too messy for comfort. I think we should just > > revert the whole thing and quirk that one icl machine. > > Alright sure. > > Can this be done is same patch, I mean no need for a revert and a > separate quirk patch, right? Separate revert seems cleaner to me. And then one can actually backport the quirk without having to also backport the already reverted commit. Though I haven't checked how far the bad commit already got backported. -- Ville Syrjälä Intel