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 A4761CCF9F8 for ; Thu, 30 Oct 2025 17:09:39 +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=4w9aXiKjI89pMzEIR8e5AXsnw+Rk32++svRr0dS35+4=; b=gRE0Ca7o2tBXsV JhTz2zkG3cCuOcvdTltAAJoRPSUJ8GedU6kMj0Z8SvQL3sPbMPwRIExd3wuUF2vx29jbqzmRVW+h6 BtgSIbrs1qIGVg6sGDMre0th10xEhmUInwASlBd5FzoskuYbY4XHOS5eibLgBa02XgCBgiBsl38n1 La83scw1zOjESwXyjKsv+JfIz+00VNPOfaRVYg8BosgSQtCCpARsoNNi/rkQyqUSkpw9m23jBQh93 Q2pjAmuY6mqkU521XIPgXJlDrY/QkKUfbG7VXfRBf0eMteI8ZW1x1A1yKIWf3GmtaCxJs6IE6eNWz tUmSMddEC/LltC28j/FA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vEW9b-00000004W9U-1dfE; Thu, 30 Oct 2025 17:09:39 +0000 Received: from smtpout-04.galae.net ([185.171.202.116]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vEW9Y-00000004W8a-1T8l for linux-i3c@lists.infradead.org; Thu, 30 Oct 2025 17:09:38 +0000 Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-04.galae.net (Postfix) with ESMTPS id 9E24AC0DABA; Thu, 30 Oct 2025 17:09:11 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 0928460331; Thu, 30 Oct 2025 17:09:32 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id DF1D411808CCF; Thu, 30 Oct 2025 18:09:29 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1761844171; h=from:subject:date:message-id:to:cc:mime-version:content-type: in-reply-to:references; bh=ueUINSeERYMDlNo5jcT9YJikDS5HY4Egk6Xzi3ktbrk=; b=IWcG3iNLJg3miWAgUI4OIZJ0PqYFi7ScAgZyYXfaXb0VCfSv4wMA7gGuc6+YRIW6f0a4LW DWRjdNBGs99ci1NOHdaM945YZ+qONx6YUTI0/eOzljDj64x4x2N4IOf1guClxCF/3jZ55m hQIF+StGUWU5zgjyFVVn695K4JpUUDyzhYesax/JIR0mwQRu1dLIjrhZssGFA1xt1x3Qs4 dEaPmPAzPiU8YHKA0gwVEnn3ukq/7Yfzn+KXuZTkUH8Eqc3g94qvbGVTrxnTjg6CahDX6g JNl7VOrmKQkDpYSfPpzOvFBXctQWvxbJLRt0fKEmT8CZnBWSw25vl36B2WEObQ== Date: Thu, 30 Oct 2025 18:09:29 +0100 From: Alexandre Belloni To: Wolfram Sang Cc: adrianhoyin.ng@altera.com, dinguyen@kernel.org, Frank.Li@nxp.com, linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] i3c: dw: add option to disable runtime PM for DesignWare I3C controller Message-ID: <20251030170929b5991b7d@mail.local> References: <22286d459959f2a153ac59d7da46794c0f495c77.1760579799.git.adrianhoyin.ng@altera.com> <20251016071051c3f647ce@mail.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251030_100936_558275_6D9A85A4 X-CRM114-Status: GOOD ( 21.47 ) X-BeenThere: linux-i3c@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-i3c" Errors-To: linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org On 16/10/2025 09:37:53+0200, Wolfram Sang wrote: > > > > Add a new Kconfig option, DW_I3C_DISABLE_RUNTIME_PM, that allows > > > disabling all runtime power management (PM) operations for the > > > Synopsys DesignWare I3C controller. When this option is selected, > > > the driver skips all runtime PM calls such as pm_runtime_enable(), > > > pm_runtime_get(), and pm_runtime_put(), keeping the controller > > > permanently active. > > > > While the quirk may make sense, it definitively can't be activated by a > > Kconfig option. This should rather be tied to a new compatible string or > > a property. > > I wondered why this is a quirk, at all, and not default behaviour. Is it > because it works with some RPM implementations and not with others, > depending on the platform? > > But even if that is the case, it might be worth to opt-in for power > management instead of opting-out for buggy behaviour. Because I would > not assume that IBI have been thoroughly tested when a new platform > using this driver gets upstream. So, the buggy behaviour may only be > recognized later. Or? > I guess it depends on how the IP has been integrated on the SoC, hence my suggestion to tie this to a compatible string. opt-in or opt-out, I don't care too much but seeing this seems to work for AMD, we need to keep the existing behaviour for them. -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com -- linux-i3c mailing list linux-i3c@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-i3c