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 392DFC7EE2A for ; Tue, 24 Jun 2025 16:50:05 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E132B10E5F1; Tue, 24 Jun 2025 16:50:04 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="LZuXgrgC"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) by gabe.freedesktop.org (Postfix) with ESMTPS id A46D510E0DB; Tue, 24 Jun 2025 16:50:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1750783804; x=1782319804; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=ZvqGwqjppbPHxsasoX+zoTaf4RAOUb2sHbUJ+fb5/QQ=; b=LZuXgrgC0T2utCdfDAh/7aGhu+78q+poiIySPSpQVgw4rs95VkRQ2c8R MCLaHcO2B9kZKo7ReNz/vkyEr0CRIrvNddd3hrq1coZanVg8MlmugzrgY 1oddp2quiQoqiRynmaMa4/a1X6TAS8g0RTfenSfHXD2XDOIfrByN8HsWE Ihmv31B7GS8m+v2y5SPxvPUKr6ymtF3alLiQUhxrOHW1BpbWjUR03kHJU dJxm7leoFzZQzPUSDWZvwrz5hTcuUBRYkrIFENI1hY6ZLFIImSNb+0veU LrZsTuLbncx8+5puj2IHlUUMAwFP1yfL53zCtr1xB9BKEJy1GnB8flwAe A==; X-CSE-ConnectionGUID: gy1/S//kQ9mKJ4nntTDx4Q== X-CSE-MsgGUID: euTFOX0fSGW0QfngP7ocoA== X-IronPort-AV: E=McAfee;i="6800,10657,11474"; a="56818911" X-IronPort-AV: E=Sophos;i="6.16,262,1744095600"; d="scan'208";a="56818911" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2025 09:50:03 -0700 X-CSE-ConnectionGUID: GOUltRKNQs6JEQDqg2EgRQ== X-CSE-MsgGUID: q/8If8CoQMCTthIdha9UDQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,262,1744095600"; d="scan'208";a="157748171" Received: from vpanait-mobl.ger.corp.intel.com (HELO stinkbox) ([10.245.245.73]) by orviesa005.jf.intel.com with SMTP; 24 Jun 2025 09:50:01 -0700 Received: by stinkbox (sSMTP sendmail emulation); Tue, 24 Jun 2025 19:49:59 +0300 Date: Tue, 24 Jun 2025 19:49:59 +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, Jani Nikula Subject: Re: [PATCH 1/2] Revert "drm/i915/dp: Reject HBR3 when sink doesn't support TPS4" Message-ID: References: <20250620124417.2041233-1-ankit.k.nautiyal@intel.com> <20250620124417.2041233-2-ankit.k.nautiyal@intel.com> <5fe0cd00-291b-4e93-a93a-6f8e32db4541@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5fe0cd00-291b-4e93-a93a-6f8e32db4541@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, Jun 24, 2025 at 10:10:53AM +0530, Nautiyal, Ankit K wrote: > > On 6/23/2025 8:12 PM, Ville Syrjälä wrote: > > On Fri, Jun 20, 2025 at 06:14:16PM +0530, Ankit Nautiyal wrote: > >> This reverts commit 584cf613c24a4250d9be4819efc841aa2624d5b6. > >> Commit 584cf613c24a ("drm/i915/dp: Reject HBR3 when sink doesn't support > >> TPS4") introduced a blanket rejection of HBR3 link rate when the sink does > >> not support TPS4. While this was intended to address instability observed > >> on certain eDP panels [1], the TPS4 requirement is only mandated for DPRX > >> and not for eDPRX. > > I see no exception given for eDP regarding this rule. The only exception > > allowed is that eDP can say DPCD_REV=1.4 + TPS4_SUPPORTED=0. So I still > > claim that these eDP sinks are violating the spec. > > Hmm.. Yes the spec allows eDP sinks to report DPCD_REV=1.4 and > TPS4_SUPPORTED, so perhaps eDPs claiming HBR3 with DPCD rev other than > rev 1.4 and not supporting TPS4 are indeed violating the spec. > > Would it make sense to add a condition that checks for DPCD_REV=1.4. > > Specifically: > > if DPCD_REV=1.4 and TPS4_SUPPORTED = 0, then do not prune the HBR3 rate? > > Or otherway if DPCD_REV!=1.4 and TPS4_SUPPORTER = 0, prune the HBR3 rate > > This way the patch need not be reverted, but modified to address > instability issues for eDP panels that are not aligned with the spec. > > That said, the gitlab issue#5969 [1] will still need another solution > since it seems to have DPCD rev 14 as per logs: > > DPCD: 14 1e 44 41 00 00 01 80 02 00 02 00 00 0b 80 I think we do need the quirk. But the commit message should IMO be adjusted so that it doesn't claim that these panels are 100% legal. -- Ville Syrjälä Intel