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From: Andrew Lunn <andrew@lunn.ch>
To: Yunsheng Lin <linyunsheng@huawei.com>
Cc: davem@davemloft.net, f.fainelli@gmail.com,
	huangdaode@hisilicon.com, xuwei5@hisilicon.com,
	liguozhu@hisilicon.com, Yisen.Zhuang@huawei.com,
	gabriele.paoloni@huawei.com, john.garry@huawei.com,
	linuxarm@huawei.com, salil.mehta@huawei.com,
	lipeng321@huawei.com, tremyfr@gmail.com, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH NET V5 2/2] net: hns: Use phy_driver to setup Phy loopback
Date: Tue, 27 Jun 2017 15:29:58 +0200	[thread overview]
Message-ID: <20170627132958.GA9921@lunn.ch> (raw)
In-Reply-To: <17132762-9b94-bc32-fee8-e90a6db5762a@huawei.com>

> >> -		phy_write(phy_dev, COPPER_CONTROL_REG, val);
> >> +		err = phy_resume(phy_dev);
> > 
> > Maybe this was discussed with an earlier version of these patches. Why
> > are using phy_resume() and phy_suspend()?
> When self_test is invoked with ETH_TEST_FL_OFFLINE option, hns mac driver
> call dev_close to set net dev to offline state if net dev is online.
> Doing the actual phy loolback test require phy is power up, So phy_resume
> and phy_suspend are used.

O.K, so you at least need some comments, because this is not obvious.

>From your description, it sounds like you can call phy_resume() on a
device which is not suspended. In general, suspend is expected to
store away state which will be lost when powering down a
device. Resume writes that state back into the device after it is
powered up. So resuming a device which was never suspended could write
bad state into it.

Also, what about if WOL has been set before closing the device?

      Andrew

  reply	other threads:[~2017-06-27 13:30 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-26  2:10 [PATCH NET V5 0/2] Add loopback support in phy_driver and hns ethtool fix Lin Yun Sheng
2017-06-26  2:10 ` [PATCH NET V5 1/2] net: phy: Add phy loopback support in net phy framework Lin Yun Sheng
2017-06-26 13:43   ` Andrew Lunn
2017-06-26 16:45   ` Florian Fainelli
2017-06-26  2:10 ` [PATCH NET V5 2/2] net: hns: Use phy_driver to setup Phy loopback Lin Yun Sheng
2017-06-26 13:42   ` Andrew Lunn
2017-06-27  3:25     ` Yunsheng Lin
2017-06-27 13:29       ` Andrew Lunn [this message]
2017-06-28  0:59         ` Yunsheng Lin
2017-06-28 20:28           ` Andrew Lunn
2017-06-29  2:35             ` Yunsheng Lin
2017-06-29 13:56               ` Andrew Lunn
2017-06-30  9:14                 ` Yunsheng Lin
2017-06-30 13:39                   ` Andrew Lunn
2017-07-01 15:17                     ` Andrew Lunn
2017-07-03  9:57                       ` Yunsheng Lin

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