Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934531AbeAKQAH (ORCPT + 1 other); Thu, 11 Jan 2018 11:00:07 -0500 Received: from mail-qt0-f193.google.com ([209.85.216.193]:39731 "EHLO mail-qt0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933608AbeAKQAE (ORCPT ); Thu, 11 Jan 2018 11:00:04 -0500 X-Google-Smtp-Source: ACJfBosHPuA9w8PYk4h8NTKIBekGqHk0lnhK8lIZfHgAAwGMzCS9rXI2rOhmhs6dvIgskecPyxIOqlgJPkwMA1JH+EE= MIME-Version: 1.0 In-Reply-To: References: <1515496281-10988-1-git-send-email-geert+renesas@glider.be> <20180111.104835.381039264896352436.davem@davemloft.net> <20180111155316.GV17719@n2100.armlinux.org.uk> From: Geert Uytterhoeven Date: Thu, 11 Jan 2018 17:00:03 +0100 X-Google-Sender-Auth: g19h9gyNtWdYHTFCPYjpyxdYpWE Message-ID: Subject: Re: [PATCH] net: phy: Fix phy_modify() semantic difference fallout To: Russell King - ARM Linux Cc: David Miller , Geert Uytterhoeven , Andrew Lunn , Florian Fainelli , netdev , Linux-Renesas , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Thu, Jan 11, 2018 at 4:54 PM, Geert Uytterhoeven wrote: > On Thu, Jan 11, 2018 at 4:53 PM, Russell King - ARM Linux > wrote: >> On Thu, Jan 11, 2018 at 10:48:35AM -0500, David Miller wrote: >>> From: Geert Uytterhoeven >>> Date: Tue, 9 Jan 2018 12:11:21 +0100 >>> >>> > In case of success, the return values of (__)phy_write() and >>> > (__)phy_modify() are not compatible: (__)phy_write() returns 0, while >>> > (__)phy_modify() returns the old PHY register value. >>> > >>> > Apparently this change was catered for in drivers/net/phy/marvell.c, but >>> > not in other source files. >>> > >>> > Hence genphy_restart_aneg() now returns 4416 instead zero, which is >>> > considered an error: >>> > >>> > ravb e6800000.ethernet eth0: failed to connect PHY >>> > IP-Config: Failed to open eth0 >>> > IP-Config: No network devices available >>> > >>> > Fix this by converting positive values to zero in all callers of >>> > phy_modify(). >>> > >>> > Fixes: fea23fb591cce995 ("net: phy: convert read-modify-write to phy_modify()") >>> > Signed-off-by: Geert Uytterhoeven >>> > --- >>> > Alternatively, __phy_modify() could be changed to follow __phy_write() >>> > semantics? >>> >>> I really want a resolution to this quickly, this broke lots of stuff >>> for people. >>> >>> __phy_modify() wants to return multiple values, so it should be coded >>> up to do so explicitly rather than trying to encode two values from >>> overlapping value spaces in one return value. >>> >>> That means the original value should be returned by-reference. And >>> this will make the error/no-error return value unambiguous. >>> >>> int __phy_modify(struct phy_device *phydev, u32 regnum, u16 mask, u16 set, >>> u16 *orig_val); >> >> I'm sorry I have no time to work on this right now due to the meltdown >> and spectre stuff that hit last week. If you need to do something, >> please revert both the mvneta series and the series containing this >> patch. > > I'll have a look into it... Sorry, the phy_restore_page() semantics are driving me crazy. Let's revert. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds