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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 BAB2AFF8860 for ; Mon, 27 Apr 2026 19:10:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Rb4LC4RoKjMwkAoMYkZMORsdxxUBkkBcuhhkQcQ9qHU=; b=x9XsLwl+qMR4sfu/+uhhu0U62a 5jJ0Ox5kN2pjDy23A+hikyuin7aZODHzPz7Viw5dmFfBExuX69Dbt+XYBQlpckpCNXBxBVXOC8Dq6 qK93Dxid1M6VThU4OfhXq6fQY1jhBl1CcV7fFC8UoEUpjhSFfiiqKEdN/c5Iqd+nzRnfFH6ZWlBIF b+YhBNJHIGklRphLGfs7br7lnX++AghLVS35qOITb2+SjQkcCPU4ae7su0tFNY7PYIH4prcZSdmw9 NTy2H1qzh22EowL1OhDIEUSMboPCMxbNT8ezHNNl4RknFEqONfP6Enn7icGfseDixmmljjX6PwxAZ 61sZnewQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wHRLK-00000000271-46SA; Mon, 27 Apr 2026 19:10:06 +0000 Received: from gloria.sntech.de ([185.11.138.130]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wHRLI-0000000025o-2uuQ; Mon, 27 Apr 2026 19:10:05 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sntech.de; s=gloria202408; h=Content-Type:Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Reply-To; bh=Rb4LC4RoKjMwkAoMYkZMORsdxxUBkkBcuhhkQcQ9qHU=; b=VaiZ0EuMs/V/UpaUqhIxQT4kOQ m2fmNRxLnBGy786PBF2Z0XkvBMAdhyEjrVoKui6GQ8giNSHAgxOJ65AnNm08rjG9ZcemAVGmlbYo/ x0vLZwJUF06BH6iWuyebP6piC19SdZ3GLQlXRGSEATGAP7cM7uguCYD7l8bg82hup8QcS5AT6NLAK O1rudfGXB/blSVVheseL8grFMm70H+C1ElnAg1J4VOHI1ueOm2U+FYROlQkL8Vzg77Rlg4y8VwKlq IekUEQ9uAOQ5SFiBYkhiDulThCYOT1lPRHpbX2efjvngHBt09pilTEDB+hXdcnKs1SbNOdXWus5zo 4MNyAfbg==; From: Heiko Stuebner To: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Sandy Huang , Andy Yan , Cristian Ciocaltea Cc: kernel@collabora.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, Diederik de Haas , Maud Spierings Subject: Re: [PATCH v5 05/10] drm/bridge: dw-hdmi-qp: Add HDMI 2.0 SCDC scrambling and high TMDS clock ratio support Date: Mon, 27 Apr 2026 21:09:09 +0200 Message-ID: <890451008.0ifERbkFSE@phil> In-Reply-To: References: <20260426-dw-hdmi-qp-scramb-v5-0-d778e70c317b@collabora.com> <3826043.PYKUYFuaPT@phil> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260427_121004_764703_F7527100 X-CRM114-Status: GOOD ( 27.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Am Montag, 27. April 2026, 18:39:44 Mitteleurop=C3=A4ische Sommerzeit schri= eb Cristian Ciocaltea: > Hello Heiko, >=20 > Thanks for the quick reviews! >=20 > On 4/27/26 1:49 PM, Heiko Stuebner wrote: > > Am Sonntag, 26. April 2026, 02:20:17 Mitteleurop=C3=A4ische Sommerzeit = schrieb Cristian Ciocaltea: > >> Enable HDMI 2.0 display modes (e.g. 4K@60Hz) by adding SCDC management > >> for the high TMDS clock ratio and scrambling, required when the TMDS > >> character rate exceeds the 340 MHz HDMI 1.4b limit. > >> > >> A periodic work item monitors the sink's scrambling status to recover > >> from sink-side resets. On hotplug detect, if SCDC scrambling state is > >> out of sync with the driver, trigger a CRTC reset to re-establish the > >> link. > >> > >> Reject modes requiring TMDS rates above 600 MHz, as those fall in the > >> HDMI 2.1 FRL domain which is not supported. In no_hpd configurations, > >> further restrict to 340 MHz since SCDC requires a connected sink. > >> > >> Tested-by: Diederik de Haas > >> Tested-by: Maud Spierings > >> Signed-off-by: Cristian Ciocaltea > >> --- > >> drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 188 ++++++++++++++++++= ++++++--- > >> 1 file changed, 172 insertions(+), 16 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gp= u/drm/bridge/synopsys/dw-hdmi-qp.c > >> index d649a1cf07f5..c482a8e7da25 100644 > >> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c > >> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c > >> @@ -2,6 +2,7 @@ > >> /* > >> * Copyright (c) 2021-2022 Rockchip Electronics Co., Ltd. > >> * Copyright (c) 2024 Collabora Ltd. > >> + * Copyright (c) 2025 Amazon.com, Inc. or its affiliates. > >=20 > > I have no real clue about the inner workings of hdmi, but that line > > does make me curious, because no part of the patch authorship does > > mention Amazon ;-) . >=20 > That was intentional: although the code was written by Collabora, the cop= yright > belongs to Amazon. They selected a nice chip then :-D > > Also I think "or it's affiliates" might be way too broad, because this > > can be essentially everyone. So noone in the future will know who to > > ask on copyright questions. > >=20 > > Similarly when _somebody_ comes forward with "I hold a copyright on thi= s" > > no-one could verify this claim as well. > >=20 > > I somehow expect _one_ entity being specified, not possibly hundreds. >=20 > Hmm, I followed the wording already used elsewhere in the kernel tree: >=20 > $ git grep 'Copyright.*Amazon.*affiliates' | wc -l > 93 >=20 > There appears to be only a single instance that omits =E2=80=9Caffiliates= =E2=80=9D: >=20 > $ git grep 'Copyright.*Amazon' | grep -v affiliates > drivers/power/supply/max14656_charger_detector.c: * Copyright (C) Amazon = Technologies Inc. All rights reserved. >=20 > Which was added nearly ten years ago, so I=E2=80=99m not sure it makes se= nse to adopt > that form now. >=20 > Actually, this seems to be fairly common among other vendors as well: >=20 > $ git grep 'Copyright.*affiliates' | wc -l > 1014 okay then ... if that is already used a lot, and nobody else complained then it should be fine I guess :-) . It just sounded strange to me when reading that earlier. Thanks a lot for digging those stats up Heiko