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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A71CECAAD8 for ; Fri, 23 Sep 2022 04:20:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232268AbiIWEUp (ORCPT ); Fri, 23 Sep 2022 00:20:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229810AbiIWEUo (ORCPT ); Fri, 23 Sep 2022 00:20:44 -0400 Received: from bmailout2.hostsharing.net (bmailout2.hostsharing.net [83.223.78.240]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 419C7F3100; Thu, 22 Sep 2022 21:20:42 -0700 (PDT) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS DV RSA Mixed SHA256 2020 CA-1" (verified OK)) by bmailout2.hostsharing.net (Postfix) with ESMTPS id 31C39280973F2; Fri, 23 Sep 2022 06:20:37 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 1690F4EA97; Fri, 23 Sep 2022 06:20:37 +0200 (CEST) Date: Fri, 23 Sep 2022 06:20:37 +0200 From: Lukas Wunner To: Florian Fainelli Cc: Marek Szyprowski , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Eric Dumazet , netdev@vger.kernel.org, linux-usb@vger.kernel.org, Steve Glendinning , UNGLinuxDriver@microchip.com, Oliver Neukum , Andre Edich , Oleksij Rempel , Martyn Welch , Gabriel Hojda , Christoph Fritz , Lino Sanfilippo , Philipp Rosenberger , Heiner Kallweit , Andrew Lunn , Russell King , Ferry Toth , Krzysztof Kozlowski , 'Linux Samsung SOC' Subject: Re: [PATCH net-next v3 5/7] usbnet: smsc95xx: Forward PHY interrupts to PHY driver to avoid polling Message-ID: <20220923042037.GA10101@wunner.de> References: <20220826071924.GA21264@wunner.de> <2b1a1588-505e-dff3-301d-bfc1fb14d685@samsung.com> <20220826075331.GA32117@wunner.de> <093730dd-2f2c-bd0b-bd13-b97f8a2898bd@samsung.com> <81c0f21f-f8f1-f7b3-c52f-c6a564c6a445@samsung.com> <20220918191333.GA2107@wunner.de> <20220918205516.GA13914@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org On Sun, Sep 18, 2022 at 03:11:47PM -0700, Florian Fainelli wrote: > On 9/18/2022 1:55 PM, Lukas Wunner wrote: > > On Sun, Sep 18, 2022 at 01:41:13PM -0700, Florian Fainelli wrote: > > > On 9/18/2022 12:13 PM, Lukas Wunner wrote: > > > > On Mon, Aug 29, 2022 at 01:40:05PM +0200, Marek Szyprowski wrote: > > > > > I've finally traced what has happened. I've double checked and indeed > > > > > the 1758bde2e4aa commit fixed the issue on next-20220516 kernel and as > > > > > such it has been merged to linus tree. Then the commit 744d23c71af3 > > > > > ("net: phy: Warn about incorrect mdio_bus_phy_resume() state") has been > > > > > merged to linus tree, which triggers a new warning during the > > > > > suspend/resume cycle with smsc95xx driver. Please note, that the > > > > > smsc95xx still works fine regardless that warning. However it look that > > > > > the commit 1758bde2e4aa only hide a real problem, which the commit > > > > > 744d23c71af3 warns about. > > > > > > > > > > Probably a proper fix for smsc95xx driver is to call phy_stop/start > > > > > during suspend/resume cycle, like in similar patches for other drivers: > > > > > > > > > > https://lore.kernel.org/all/20220825023951.3220-1-f.fainelli@gmail.com/ > > > > > > > > No, smsc95xx.c relies on mdio_bus_phy_{suspend,resume}() and there's > > > > no need to call phy_{stop,start}() > > > > > 744d23c71af3 was flawed and 6dbe852c379f has already fixed a portion > > > > of the fallout. > > > > > > > > However the WARN() condition still seems too broad and causes false > > > > positives such as in your case. In particular, mdio_bus_phy_suspend() > > > > may leave the device in PHY_UP state, so that's a legal state that > > > > needs to be exempted from the WARN(). > > > > > > How is that a legal state when the PHY should be suspended? Even if we are > > > interrupt driven, the state machine should be stopped, does not mean that > > > Wake-on-LAN or other activity interrupts should be disabled. > > > > mdio_bus_phy_suspend() > > phy_stop_machine() > > phydev->state = PHY_UP # if (phydev->state >= PHY_UP) > > > > So apparently PHY_UP is a legal state for a suspended PHY. > > It is not clear to me why, however. Sure it does ensure that when we resume > we set needs_aneg = true but this feels like a hack in the sense that we are > setting the PHY in a provisional state in anticipation for what might come > next. I've just submitted a fix so that at least v6.0 doesn't get released with a false-positive WARN splat on resume: https://lore.kernel.org/netdev/8128fdb51eeebc9efbf3776a4097363a1317aaf1.1663905575.git.lukas@wunner.de/ I guess we can look into making the state setting more logical in a separate step. > > > If you allow PHY_UP, then the warning becomes effectively useless, so I > > > don't believe this is quite what you want to do here. > > > > Hm, maybe the WARN() should be dropped altogether? > > And then be left with debugging similar problems that prompted me to submit > the patch in the first place, no thank you. I guess I would rather accept > that PHY_UP needs to be special cased then. I've interpreted that as an Acked-by for exempting PHY_UP. If that was not what you wanted, please speak up. Thanks, Lukas