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 665BBCA5FEC for ; Sun, 4 Oct 2026 10:52:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=vm5MRR+nphz/8zleYRKGUQJxGFPa1j0Ot1fuyL+gQ7o=; b=guaCSnseUx/aj3 LVz4JoQpgKcRoXow0kIlZIoXbt7OkVT1UpYajAVgZwLbHVTW9aFpV1CXRt3IsB6JIWn8vQLL2psq0 H06Jt9u2F88T8+TYTsNFjsvnGSrsbUo7hpyD//Mr0fF/I5ki5NpJ1VzDPA5qIcbb/UCWRxYDXJw/n VzojNM2qN2MngHmAA76cp2tUU6nMvaX6dG1hW1lzZtjCh0WjCellbM9s2nTcwBxWJKitivswvapB3 zgFjWoAwXLHX18nP80IUQXaL35cRzuphRstEeS2Kl4/kZM/V5+Kx75IGO0g5aa8i9PISbm19xir5u aWlNcITlPhgnKArBkqqg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDJpF-0000000EgE7-2byY; Sun, 04 Oct 2026 10:52:13 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDJpE-0000000EgCq-1SbB; Sun, 04 Oct 2026 10:52:12 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id C73CA429D5; Sun, 4 Oct 2026 10:52:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A0C51F000FF; Sun, 4 Oct 2026 10:52:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791111131; bh=Ded2t/lxa5/OOJ87UbsbJnDc5Xdi5OA3X44Xyk2z2B0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FFLg41iwcTX3eTrwV8t5ajXGLkgtY0ZvuL5T/qeDdnKQBwVWD6N5vCzTPBYi+bBZY 05fFRj3tAJZR+cbH5AyVdJa2W40q3K3/wb9BimQtqdglNKNr8+LXBwCiacs6srl2OR D1nb+Bqi7YFJkK8yerA5MXws9WGktv/Pf3ROeJSV0kVYffAZuT0/PNGgMQx5+u214k A7n7yhaCNIk/le8m+R9bbMMpGoc9Bfk21DQzyv2XNzjpVvTYeobV8hfnxfA8c0sh0c 1v8WYrvs0C4AMhH4LDWpQBYsyvPmHVsnuGAofGaPT4Eyd4NqyueuT98NECkdbuH0nJ vVE6AkYtBSPsw== Date: Sun, 4 Oct 2026 12:52:07 +0200 From: Vinod Koul To: Cristian Ciocaltea Cc: Neil Armstrong , Manivannan Sadhasivam , Heiko Stuebner , Andy Yan , kernel@collabora.com, linux-phy@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v2 1/3] phy: hdmi: Add optional FRL TxFFE config options Message-ID: References: <20260901-hdptx-ffe-v2-0-3a5922c76fc5@collabora.com> <20260901-hdptx-ffe-v2-1-3a5922c76fc5@collabora.com> <3c0dc77b-b692-498e-aed6-aa97d827b2f4@collabora.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <3c0dc77b-b692-498e-aed6-aa97d827b2f4@collabora.com> X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org On 04-10-26, 00:33, Cristian Ciocaltea wrote: > Hi Vinod, > > On 10/3/26 11:39 PM, Vinod Koul wrote: > > On 01-09-26, 22:55, Cristian Ciocaltea wrote: > >> During HDMI 2.1 FRL link training, the source and sink can negotiate a > >> Transmitter Feed-Forward Equalization (TxFFE) level to improve the > >> signal quality. Starting from zero, the source may increment the TxFFE > >> level up to a maximum agreed during the LTS3 stage if the sink keeps > >> reporting FLT failures. TxFFE adjustment is optional and only attempted > >> when both the source and the connected sink support it. > >> > >> Since the existing HDMI PHY configuration API covers the FRL rate/lane > >> selection only, provide the following fields to the frl sub-struct of > >> phy_configure_opts_hdmi: > >> > >> * ffe_level: the TxFFE level to apply, only meaningful when > >> set_ffe_level is set. > >> > >> * set_ffe_level: a 1-bit flag that changes the semantics of the > >> phy_configure() call, i.e. when set, the PHY driver must apply the new > >> ffe_level and ignore the other frl related fields. > > > > The ffe_level 0 implies it is disabled, so why should we use a flag for > > this? Rather use if value valid (non zero) logic to apply..? > > That's not quite possible because level 0 is valid (and the default) according > to HDMI 2.1 spec. The source is expected to reset TxFFE to default whenever a > new FRL rate is set, hence the API shall be conformant. Ah, looks like AI gave me wrong info about 0 being invalid, this is okay then -- ~Vinod _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip 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 E2435CA5FCE for ; Sun, 4 Oct 2026 10:52:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=gOToHrJuM0Q19uZMfeT2+Qr2IReHhaqte07sTpg1Fnw=; b=bYczCrJH7mR/P/ edRu9e/46RL0uG7FVfUaW/At5oI/s2tUQTtVUr1EgEcjqW4jaX+t+XREHTHDrieslqkSTtXj+8gW9 T9/O+NAMdSleE8VA+vAg2OWJZIWUhLHpfqd/bzpFC8eMMedHlE257MEHZ9mkWlW7RldRaTDKYP+zV ONlM9BZTgaEWrqXksXZlf6BMOrw5Cu6GNTjhBPtuGeW4UJDmKi7LQ7wnBf+oCdeCZfvZzG+MSeWJ+ dr0O+tGKrVr371hBcj7vco06kxZ192LGQmtryEMZ9RICDSygAaACMlLVyp5UuI6odNCoEtBlrv11K 8i7YG1fIDTf+HY0sZWMQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDJpF-0000000EgDw-2NNj; Sun, 04 Oct 2026 10:52:13 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDJpE-0000000EgCq-1SbB; Sun, 04 Oct 2026 10:52:12 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id C73CA429D5; Sun, 4 Oct 2026 10:52:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A0C51F000FF; Sun, 4 Oct 2026 10:52:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791111131; bh=Ded2t/lxa5/OOJ87UbsbJnDc5Xdi5OA3X44Xyk2z2B0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FFLg41iwcTX3eTrwV8t5ajXGLkgtY0ZvuL5T/qeDdnKQBwVWD6N5vCzTPBYi+bBZY 05fFRj3tAJZR+cbH5AyVdJa2W40q3K3/wb9BimQtqdglNKNr8+LXBwCiacs6srl2OR D1nb+Bqi7YFJkK8yerA5MXws9WGktv/Pf3ROeJSV0kVYffAZuT0/PNGgMQx5+u214k A7n7yhaCNIk/le8m+R9bbMMpGoc9Bfk21DQzyv2XNzjpVvTYeobV8hfnxfA8c0sh0c 1v8WYrvs0C4AMhH4LDWpQBYsyvPmHVsnuGAofGaPT4Eyd4NqyueuT98NECkdbuH0nJ vVE6AkYtBSPsw== Date: Sun, 4 Oct 2026 12:52:07 +0200 From: Vinod Koul To: Cristian Ciocaltea Cc: Neil Armstrong , Manivannan Sadhasivam , Heiko Stuebner , Andy Yan , kernel@collabora.com, linux-phy@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v2 1/3] phy: hdmi: Add optional FRL TxFFE config options Message-ID: References: <20260901-hdptx-ffe-v2-0-3a5922c76fc5@collabora.com> <20260901-hdptx-ffe-v2-1-3a5922c76fc5@collabora.com> <3c0dc77b-b692-498e-aed6-aa97d827b2f4@collabora.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <3c0dc77b-b692-498e-aed6-aa97d827b2f4@collabora.com> X-BeenThere: linux-phy@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux Phy Mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-phy" Errors-To: linux-phy-bounces+linux-phy=archiver.kernel.org@lists.infradead.org On 04-10-26, 00:33, Cristian Ciocaltea wrote: > Hi Vinod, > > On 10/3/26 11:39 PM, Vinod Koul wrote: > > On 01-09-26, 22:55, Cristian Ciocaltea wrote: > >> During HDMI 2.1 FRL link training, the source and sink can negotiate a > >> Transmitter Feed-Forward Equalization (TxFFE) level to improve the > >> signal quality. Starting from zero, the source may increment the TxFFE > >> level up to a maximum agreed during the LTS3 stage if the sink keeps > >> reporting FLT failures. TxFFE adjustment is optional and only attempted > >> when both the source and the connected sink support it. > >> > >> Since the existing HDMI PHY configuration API covers the FRL rate/lane > >> selection only, provide the following fields to the frl sub-struct of > >> phy_configure_opts_hdmi: > >> > >> * ffe_level: the TxFFE level to apply, only meaningful when > >> set_ffe_level is set. > >> > >> * set_ffe_level: a 1-bit flag that changes the semantics of the > >> phy_configure() call, i.e. when set, the PHY driver must apply the new > >> ffe_level and ignore the other frl related fields. > > > > The ffe_level 0 implies it is disabled, so why should we use a flag for > > this? Rather use if value valid (non zero) logic to apply..? > > That's not quite possible because level 0 is valid (and the default) according > to HDMI 2.1 spec. The source is expected to reset TxFFE to default whenever a > new FRL rate is set, hence the API shall be conformant. Ah, looks like AI gave me wrong info about 0 being invalid, this is okay then -- ~Vinod -- linux-phy mailing list linux-phy@lists.infradead.org https://lists.infradead.org/mailman/listinfo/linux-phy 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 F2B95CA5FCE for ; Sun, 4 Oct 2026 10:52:19 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Ded2t/lxa5/OOJ87UbsbJnDc5Xdi5OA3X44Xyk2z2B0=; b=V1HKjHwJ4BTXVZflEgr0bNmb1P uHGJmhrbXxGhGp+PqFZZHN5wX3VjcxLMx5wFNkfN5zA19rieTESA3TmMQK74ssdxZqkYJnup/hVH8 g1b7m9+da0+EXo9pZJXQYmtBAV4TBT1dXCOdIlf89SH/kUj/UPma2F8vAhw95M1y0aSV0cYSxFrbI 4ikKYyQi+n/0BFeyABgwxaJCYsnvouJeL7vJYL5Rb7KNSDCUqy7ywrEf858YgF4jg+wCtn5BrQUxY YaElYJCVQ2kWsWFD4wvOXKIas+zl5gTE1Miaf1Rdl8EA4LYHzY/0eBZLDCLviTB3Kb+tHUavnrCP4 VTQMZ4uw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDJpF-0000000EgDj-20bU; Sun, 04 Oct 2026 10:52:13 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDJpE-0000000EgCq-1SbB; Sun, 04 Oct 2026 10:52:12 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id C73CA429D5; Sun, 4 Oct 2026 10:52:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A0C51F000FF; Sun, 4 Oct 2026 10:52:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791111131; bh=Ded2t/lxa5/OOJ87UbsbJnDc5Xdi5OA3X44Xyk2z2B0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FFLg41iwcTX3eTrwV8t5ajXGLkgtY0ZvuL5T/qeDdnKQBwVWD6N5vCzTPBYi+bBZY 05fFRj3tAJZR+cbH5AyVdJa2W40q3K3/wb9BimQtqdglNKNr8+LXBwCiacs6srl2OR D1nb+Bqi7YFJkK8yerA5MXws9WGktv/Pf3ROeJSV0kVYffAZuT0/PNGgMQx5+u214k A7n7yhaCNIk/le8m+R9bbMMpGoc9Bfk21DQzyv2XNzjpVvTYeobV8hfnxfA8c0sh0c 1v8WYrvs0C4AMhH4LDWpQBYsyvPmHVsnuGAofGaPT4Eyd4NqyueuT98NECkdbuH0nJ vVE6AkYtBSPsw== Date: Sun, 4 Oct 2026 12:52:07 +0200 From: Vinod Koul To: Cristian Ciocaltea Cc: Neil Armstrong , Manivannan Sadhasivam , Heiko Stuebner , Andy Yan , kernel@collabora.com, linux-phy@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v2 1/3] phy: hdmi: Add optional FRL TxFFE config options Message-ID: References: <20260901-hdptx-ffe-v2-0-3a5922c76fc5@collabora.com> <20260901-hdptx-ffe-v2-1-3a5922c76fc5@collabora.com> <3c0dc77b-b692-498e-aed6-aa97d827b2f4@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3c0dc77b-b692-498e-aed6-aa97d827b2f4@collabora.com> 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 On 04-10-26, 00:33, Cristian Ciocaltea wrote: > Hi Vinod, > > On 10/3/26 11:39 PM, Vinod Koul wrote: > > On 01-09-26, 22:55, Cristian Ciocaltea wrote: > >> During HDMI 2.1 FRL link training, the source and sink can negotiate a > >> Transmitter Feed-Forward Equalization (TxFFE) level to improve the > >> signal quality. Starting from zero, the source may increment the TxFFE > >> level up to a maximum agreed during the LTS3 stage if the sink keeps > >> reporting FLT failures. TxFFE adjustment is optional and only attempted > >> when both the source and the connected sink support it. > >> > >> Since the existing HDMI PHY configuration API covers the FRL rate/lane > >> selection only, provide the following fields to the frl sub-struct of > >> phy_configure_opts_hdmi: > >> > >> * ffe_level: the TxFFE level to apply, only meaningful when > >> set_ffe_level is set. > >> > >> * set_ffe_level: a 1-bit flag that changes the semantics of the > >> phy_configure() call, i.e. when set, the PHY driver must apply the new > >> ffe_level and ignore the other frl related fields. > > > > The ffe_level 0 implies it is disabled, so why should we use a flag for > > this? Rather use if value valid (non zero) logic to apply..? > > That's not quite possible because level 0 is valid (and the default) according > to HDMI 2.1 spec. The source is expected to reset TxFFE to default whenever a > new FRL rate is set, hence the API shall be conformant. Ah, looks like AI gave me wrong info about 0 being invalid, this is okay then -- ~Vinod