From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E2D910E5 for ; Fri, 3 Nov 2023 01:47:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=selfnet.de header.i=@selfnet.de header.b="bjoNWvY1" Received: from mail-1.server.selfnet.de (mail-1.server.selfnet.de [141.70.126.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6EEC2198; Thu, 2 Nov 2023 18:47:48 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 43838402F7; Fri, 3 Nov 2023 02:47:39 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=selfnet.de; s=selfnet; t=1698976060; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CS7Jy0RmpWKZtYX8kkokoR7rFAe5FlYr840NCfh7jGU=; b=bjoNWvY1keqSIO+m4yp4akMI8QlxQKPYRDoRp7Sbh27P0kcta/SNNIil/fQ05zb4hUd6Dy baeWW5qpvJ0PDcWeesr48kSrYdMsQbqNycpQouOLmy8WnYCRQllZkXIU8yOwBXvwnU8t6q 7w8h1lQ+EHb9wiCkB566Giv30kjc7Mo6XkgdA1rGTgERPV51TIcxNcRaednOD80w3ApvA1 j5npJUb2BReiEmkJod2HYzgl+XpZF/IQAy8vQvInaqld2Gnk2Xe8lSoV5VOzZNyxafEyJy /l3Cz+Jxz7DEEOt8JaGIrR5rkcaj1F6WLNYoVE1o/tIqttNXYNsng6ttRjl8Zg== Authentication-Results: mail-1.server.selfnet.de; auth=pass smtp.auth=marcovr smtp.mailfrom=marcovr@selfnet.de From: Marco von Rosenberg To: Andrew Lunn Cc: Florian Fainelli , Broadcom internal kernel review list , Heiner Kallweit , Russell King , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Marco von Rosenberg Subject: Re: [PATCH] net: phy: broadcom: Wire suspend/resume for BCM54612E Date: Fri, 03 Nov 2023 02:47:38 +0100 Message-ID: <4890615.31r3eYUQgx@5cd116mnfx> In-Reply-To: References: <20231030225446.17422-1-marcovr@selfnet.de> <5414570.Sb9uPGUboI@5cd116mnfx> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On Wednesday, November 1, 2023 11:06:56 PM CET Andrew Lunn wrote: > On Wed, Nov 01, 2023 at 10:42:52PM +0100, Marco von Rosenberg wrote: > > On Tuesday, October 31, 2023 1:31:11 AM CET Andrew Lunn wrote: > > > Are we talking about a device which as been suspended? The PHY has > > > been left running because there is no suspend callback? Something then > > > triggers a resume. The bootloader then suspends the active PHY? Linux > > > then boots, detects its a resume, so does not touch the hardware > > > because there is no resume callback? The suspended PHY is then > > > useless. > > > > Hi Andrew, > > > > thanks for your feedback. I guess a bit of context is missing here. The > > issue has nothing to do with an ordinary suspension of the OS. The main > > point is that on initial power-up, the bootloader suspends the PHY before > > booting Linux. With a resume callback defined, Linux would call it on > > boot and make the PHY usable. > > Ah, so you rely on phy_attach_direct() calling phy_resume(phydev). > > This seems an odd way to solve the problem. It was not Linux which > suspend the PHY, so using resume is asymmetric. > > I think soft_reset() or config_init() should be taking the PHY out of > suspend. I agree with all of your points. This is just one way which happens to solve this specific problem. Of course it might be asymmetric to see the patch as a solution to my problem. However is there anything fundamentally wrong with adding suspend/resume callbacks? I see some other drivers having these callbacks defined and some not (it seems a bit inconsistent throughout the drivers in broadcom.c to be honest). I'm wondering if I should just omit this whole "motivation" paragraph in the commit message and just use the commit message of commit 38b6a9073007 ("net: phy: broadcom: Wire suspend/resume for BCM50610 and BCM50610M") as a template. I mean, regardless of my motivation, I would say it makes sense for this PHY to support suspend and resume. Marco