netdev - Re: [PATCH net] amd-xgbe: read STAT1 register twice to get correct value

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Message-ID: <4f54056f-dac4-4ad8-8f87-0837334d1b01@lunn.ch>
Date: Fri, 15 Sep 2023 14:41:12 +0200
From: Andrew Lunn <andrew@...n.ch>
To: Raju Rangoju <Raju.Rangoju@....com>
Cc: netdev@...r.kernel.org, davem@...emloft.net, edumazet@...gle.com,
	kuba@...nel.org, pabeni@...hat.com, Shyam-sundar.S-k@....com
Subject: Re: [PATCH net] amd-xgbe: read STAT1 register twice to get correct
 value

On Thu, Sep 14, 2023 at 09:49:44AM +0530, Raju Rangoju wrote:
> Link status is latched low, so read once to clear
> and then read again to get current state.

I don't know about your PHY implementation, but within phylib and
Linux PHY drivers, this is considered wrong. You loose out on being
notified of the link going down and then back up again. Or up and then
down again.

But since this is not a Linux PHY driver, you are free to do whatever
you want...

Also, i believe it is latched, not latched low. So i think your commit
message is wrong. You should probably check with IEEE 802.3 clause 22.

    Andrew