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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB6E6C433EF for ; Thu, 11 Nov 2021 13:56:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 907E861078 for ; Thu, 11 Nov 2021 13:56:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233640AbhKKN7Q (ORCPT ); Thu, 11 Nov 2021 08:59:16 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:45218 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233606AbhKKN7M (ORCPT ); Thu, 11 Nov 2021 08:59:12 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: kholk11) with ESMTPSA id 8FEFE1F45C72 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=collabora.com; s=mail; t=1636638982; bh=KL910SP64J7G4Wb7kjnHDqpyVus2MRcEbakn+kqdIos=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=U8XhgZf2aG7UA6FkTnLmxTDwrgfC2Tz/rnIRee255WLCLeL3/pCWUYD8a6clcyhhc 0JfDUkVdl3PrpypTjoPk+wJxJO+FHvb9iOY16HBynUhzC7HUspx4IzAAK/097BcW7F ZssPgbrv6V5XNf1IfE3z8FI9FvBb91mFb1YI7wFFHy0qBfPTskRALq1uUHmo+C0zkt +fLKPWj0QIK3SuARD1n4+W+joLWjGLBDjxnhFZxtncAkcqp/qm88NF6AEthYZtGykR f4EJxAve32QAjlXtMwCNqrzgN2+oHml+wDlgpvC/jf9qXNzx31FLnjnkX1AqH5jwzK W2ybNjaMFjeMA== Subject: Re: [RFC PATCH] soc: mediatek: Add support always on flag To: Chunfeng Yun , Matthias Brugger , Chun-Jie Chen Cc: linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org References: <20211102072058.4107-1-chunfeng.yun@mediatek.com> From: AngeloGioacchino Del Regno Message-ID: Date: Thu, 11 Nov 2021 14:56:19 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20211102072058.4107-1-chunfeng.yun@mediatek.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 02/11/21 08:20, Chunfeng Yun ha scritto: > There is a t-phy shared by PCIe and USB3 on mt8195, if the t-phy is > used by PCIe, when power off its mtcmos, need software reset it > (workaround way, usually hardware do it, but has an issue on mt8195), > but it has side effect to USB2 phy(works with USB3 phy to support > USB3.2 Gen1), so add support GENPD_FLAG_ALWAYS_ON flag, and make its > power always on; > Another reason is that USB3.2 Gen1/2 need keep power always on when > support runtime-pm due to hardware limitation until now; > > Signed-off-by: Chunfeng Yun > --- > drivers/soc/mediatek/mt8195-pm-domains.h | 2 +- > drivers/soc/mediatek/mtk-pm-domains.c | 2 ++ > drivers/soc/mediatek/mtk-pm-domains.h | 1 + > 3 files changed, 4 insertions(+), 1 deletion(-) > Hello Chunfeng, what are are the side effects on the USB2 PHY? Can you please expand? Also, wouldn't it be possible to also reset the USB2 PHY when resetting the t-phy in order to get it back up and running? Moreover, as for the USB3.2 hardware limitation... I would say that this is more like something that has to be accounted for in the USB driver, instead of the PM domains driver... unless there's some reason that stops you from doing that? Thanks, - Angelo