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 967E6D35162 for ; Wed, 1 Apr 2026 11:23:53 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2975010EB44; Wed, 1 Apr 2026 11:23:53 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="VYkqpHNP"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.11]) by gabe.freedesktop.org (Postfix) with ESMTPS id E08F910EB44; Wed, 1 Apr 2026 11:23:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1775042632; x=1806578632; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=W+T33+IRm7vdKPwhoCLSI6f9zBvxdvjCKpEdk2NZB2A=; b=VYkqpHNPMQhsKf5oy9q7o1PGMRYw4vPmr1r9fR/FimGipxAfRg84LQD+ 7SSp7V3zsRYN11y7ajwyOQC+LopPd0WjVlLIpYQynFbsKWN1BddbHNFRE 6VRdDv2a/MsX+7mFwoVDsaE6pvIkrnQZIVy5KDUDOE3MdunT1Bb9EzpwO BvDlI0AsWkijObThsGCFH1ChGQFOjJzJddVS3QsnDRJhHemmx/EgzAHM4 Ff/n/iFjsp2NT9Zo43G5Z7SEuIptrPkCTMUKQ8ZFlZIuvhIroMWP32MJe 76BLQr3os3BkGw88/vGTeS55Xmv2c8gb11O1BsqToSkR6h56cT5KYChtT A==; X-CSE-ConnectionGUID: tzZTHggtTB+O6MyyNMgBaA== X-CSE-MsgGUID: R0IBGkmTT8eUQRn1N6EabQ== X-IronPort-AV: E=McAfee;i="6800,10657,11745"; a="86380173" X-IronPort-AV: E=Sophos;i="6.23,153,1770624000"; d="scan'208";a="86380173" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2026 04:23:52 -0700 X-CSE-ConnectionGUID: 7GQYh0CHQuandRJdHV3cPQ== X-CSE-MsgGUID: X8kU+saVRKKmFcyLIIbD0w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,153,1770624000"; d="scan'208";a="226512302" Received: from pgcooper-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.244.199]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2026 04:23:50 -0700 Date: Wed, 1 Apr 2026 14:23:47 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Jerome Tollet Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, ankit.k.nautiyal@intel.com Subject: Re: [RESEND] drm/i915/hdmi: Poll for 200 msec for TMDS_Scrambler_Status Message-ID: References: <20260113143107.1446909-1-ankit.k.nautiyal@intel.com> <20260326054112.51287-1-jtollet@cisco.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260326054112.51287-1-jtollet@cisco.com> X-Patchwork-Hint: comment Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland 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, Mar 26, 2026 at 06:41:12AM +0100, Jerome Tollet wrote: > From: Jerome Tollet > > Hi Ankit, Ville, > > Following up on this patch. > > As previously reported, the SCDC polling approach fixes the 4K@60Hz HDMI > issue on my Alder Lake-N (N100) + Cisco Desk Pro setup, and I have not > seen regressions in testing. > > Ville, do you see any remaining concern with this approach, or is there > anything else you would like me to test to help move this forward? My main concern is having the synchronous polling appear to fix something now, and if we later make it asynchronous the original problem may re-appear. That said, after perusing the spec a bit, it looks to me that sinks should be able sync up after at most two video fields. I suppose having effectively two extra vblank waits in a full modeset sequence isn't the end of world. The extra complexity of asynchronous polling might not even be worth the hassle. But the commit message should still highlight that (AFAICS) synchronous polling is not required by the spec, and thus the fact that this fixes some monitors is sort of an accidental byproduct. -- Ville Syrjälä Intel