Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 5 Feb 2020 11:06:38 +0200
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc:     davem@davemloft.ne, mkubecek@suse.cz, jeffrey.t.kirsher@intel.com,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Jiri Pirko <jiri@mellanox.com>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Maxime Chevallier <maxime.chevallier@bootlin.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ido Schimmel <idosch@mellanox.com>,
        Jouni Hogander <jouni.hogander@unikie.com>,
        YueHaibing <yuehaibing@huawei.com>,
        Eric Dumazet <edumazet@google.com>,
        Wang Hai <wanghai26@huawei.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Li RongQing <lirongqing@baidu.com>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] net-sysfs: Ensure begin/complete are called in
 speed_show() and duplex_show()
Message-ID: <20200205090638.GS10400@smile.fi.intel.com>
References: <20200205081616.18378-1-kai.heng.feng@canonical.com>
 <20200205081616.18378-2-kai.heng.feng@canonical.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200205081616.18378-2-kai.heng.feng@canonical.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Feb 05, 2020 at 04:16:16PM +0800, Kai-Heng Feng wrote:
> Device like igb gets runtime suspended when there's no link partner. We
> can't get correct speed under that state:
> $ cat /sys/class/net/enp3s0/speed
> 1000
> 
> In addition to that, an error can also be spotted in dmesg:
> [  385.991957] igb 0000:03:00.0 enp3s0: PCIe link lost
> 
> It's because the igb device doesn't get runtime resumed before calling
> get_link_ksettings().
> 
> So let's use a new helper to call begin() and complete() like what
> dev_ethtool() does, to runtime resume/suspend or power up/down the
> device properly.
> 
> Once this fix is in place, igb can show the speed correctly without link
> partner:
> $ cat /sys/class/net/enp3s0/speed
> -1

What is the meaning of -1? Does it tells us "Hey, something is bad in hardware
I can't tell you the speed" or does it imply anything else?

Wouldn't be better to report 0?

Where is the documentation part of this ABI change?

-- 
With Best Regards,
Andy Shevchenko