Re: [PATCH V2 net-next 2/3] lan78xx: add ethtool set & get pause functions

On Mon, 2016-02-22 at 20:28 +0000, Woojung.Huh@microchip.com wrote:

quoted

-----Original Message-----
From: Ben Hutchings [mailto:ben@decadent.org.uk]
Sent: Monday, February 22, 2016 3:05 PM
To: David Miller; Woojung Huh - C21699
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH V2 net-next 2/3] lan78xx: add ethtool set & get pause
functions

On Mon, 2016-02-22 at 14:10 -0500, David Miller wrote:

quoted

From: <Woojung.Huh@microchip.com>
Date: Mon, 22 Feb 2016 18:28:18 +0000

quoted

quoted

This is incorrect; you should always return the manual settings
(fc_request_control flags) here.  If autonegotiation is enabled then
your get_settings function will return the actual pause flags.

What do you mean "return actual pause flags" when autoneg is enabled?
Pause flags set by (or default) advertise flag?

It means what was negotiated by autonegotiation, and is actually in use.

Otherwise, how can the user find out what was negotiated?

Well, actually we don't *directly* report the autonegotiation flow
control mode at present.  We report which pause flags were advertised
and what the link partner advertised, from which you can work it out.

NIC advertises pause flags via advertise register (phy reg 0x4) based on Rx & Tx flags,
and get_pauseparam() returns Rx & Tx flags set by set_pauseparm() if autonegotiation is enabled?

Yes.

quoted

Perhaps ethtool (the utility) should explicitly show what the result
is.

Ethtool -a reports Rx/Tx flags and Rx/Tx negotiated flag based on advertising and lp_advertising value.

It would probably make sense to include the result of pause frame
autonegotiation in both the 'ethtool -a' and 'ethtool' (no option)
output.

Ben.

-- 
Ben Hutchings
The generation of random numbers is too important to be left to chance.
                                                            - Robert Coveyou