From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=148.251.105.195 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793064252; b=l4LLKc63kDP7Du77/kd6+/k1DJZf5oq4msC3dfPq2FkyaN1AcSBLcWfyw3Bmbmn+HjUT JEymG0n3AapmNFzXR1ofRkZF70rFFTPKSGHaFwHkdmRz9XjsGOSeLBlLFfFWJMfD81Q+n dUbEMdAWtT3uoOoZ6LnyNM7RVBhnyfkSJ5uj+FGgKbDlu7/g0rYhslbdYgLisONzFYnUR CclpsZDvzSHgO2TCtdaiQ1FIlww5orqB9ZA1+f7mH1D2YABsxHXcKO+neY1pJ3xvzPEK6 /BFn4YgsJs/lj+ven50QpJU8p84LQvz544na7R0qpEJuqP4DOSl7z/XC0Nw2ZymHnqQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793064252; h=DMARC-Filter:DKIM-Signature:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To; bh=tLusgW45F30GPKpEKnufRsNVGgxts3xq8eyJa2O8m8g=; b=QhUNZty+EPqpFvBHraoaPBsVays2sbF35EmIH8MCHX/Q8TRNgMB/WthjsGTiBV3DgIwe npD+Ln8sndFR058ojW+VWD+5Tehg+9ZMML5rCXPNuRSrKm53UnBkWEe5hHogHuVILtjQF EcPKViNHi/LfWub/Z37FCghMa9FMj3N3QjTOhrZ79tsoZVOFcRH/1vwSKQJPQBlXORonj y5hsbndOjDacJlyW2VvxW1d2TuVAzcACqFrtT46VlxHUnqTBN4tlkuvinw/WY+6uQCT67 tYbyYdLhkWoETL05tu2KG0qCnBPKd+iweee0M2zN4nen2GKjKvOlKELnNIMXTkhI1cQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass header.d=collabora.com header.i=@collabora.com header.a=rsa-sha256 header.s=mail header.b="L/XmS78J"; arc=none smtp.remote-ip=148.251.105.195 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74589606A31A; Tue, 27 Oct 2026 01:24:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 74589606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=collabora.com header.i=@collabora.com header.a=rsa-sha256 header.s=mail header.b=L/XmS78J DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1793064243; bh=GUNzZfSn47QjR6+3HlGnMBktD45Xq2bwEqIQm3r4QF0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=L/XmS78JSeNbSM0WkCRl140w6lDTbPs3lfozlZFm8BwqrzVuH3NChgQ9yB+0U4JlC 43pfHnIRWaNVTQ9StdKqHcfPkdJwPHr/K/CKbsEuBZld4Kz6st7yUCsoTzreyGXKs8 pyOyhZarS+hMtfl5iymgpzJZ08anN1V38p8ZKUej2b1a0SqsnUy2ArD8liDPNACYeX ipgejZcT6xPVYBy5eCAPb1M7amd+UFffavzrVoSicdyAjQpf3yw9kYomnCMpRQXyfy 2wuxGBnU3Y1yX/fS8wIpHGtmmLMuc72TaoV/JdEbr2Fx+ZVHWYsD5918IP1jJWQIig hY/shSv8EmZfQ== Received: from localhost (unknown [100.64.0.241]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange secp256r1 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: cristicc) by bali.collaboradmins.com (Postfix) with ESMTPSA id 65C8217E013E; Tue, 27 Oct 2026 02:24:03 +0100 (CET) Date: Tue, 27 Oct 2026 03:23:45 +0200 From: Cristian Ciocaltea To: Lucas Tanure Cc: Maxime Ripard , Dave Stevenson , Dom Cobley , =?utf-8?B?TWHDrXJh?= Canal , Raspberry Pi Kernel Maintenance , Maarten Lankhorst , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 0/3] drm/vc4: hdmi: enable scrambling before the TMDS clock starts Message-ID: References: <20261026164028.78792-1-lucas.tanure@neat.no> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20261026164028.78792-1-lucas.tanure@neat.no> Hi Lucas, On 2026/10/26, Lucas Tanure wrote: > HDMI 2.0 asks the source to set TMDS_Bit_Clock_Ratio in the sink while > the TMDS clock is stopped and to start the clock at least 1 ms later. > vc4 writes the bit, and enables the scrambler, at the end of the enable > sequence, long after the PHY has started, and clears it before the PHY > stops. A sink that samples the bit when the clock appears never locks > a 4K60 signal from a Raspberry Pi 5, while laptops that follow the > order work on the same sink. > > Patch 3 is the fix. Patch 1 is needed on BCM2712, where phy_disable() > was an empty stub upstream, so the PHY kept running after disable; the > Raspberry Pi tree has carried this since 2024. Patch 2 fixes a > pre-existing race in the scrambling work cancel that the fix would > otherwise make easier to hit. > > v1 was tested on a Raspberry Pi 5 running the Raspberry Pi 6.18 kernel > with the same change applied, against the sink that showed the > problem: plain enable at 4K60, 1080p60 to 4K60, 4K30 to 4K60, a sink > reset and a sink power cycle all lock with zero character errors. v2 > and v3 carry the same code; the hardware test of the final form is > still pending and will be reported in this thread. Mainline was not > booted on the Pi 5. The BCM2711 path is unchanged except for the > enable order; I have no Pi 4 at hand. While converting vc4 to the common HDMI 2.0 scrambling infrastructure, I ran several tests on the Raspberry Pi 5 and didn't notice any (obvious) issues. Hence, could you please verify whether your problem reproduces with a recent mainline kernel? If it does, could you also give [1] a try and report back the actual behavior? [1] https://lore.kernel.org/lkml/20261014-vc4-common-scramb-v3-0-c68d58d959a2@collabora.com/ Regards, Cristian