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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: netdev@vger.kernel.org
Subject: genphy_read_status() vs. 1000bT Pause capability
Date: Tue, 28 Mar 2017 11:49:50 +1100	[thread overview]
Message-ID: <1490662190.3177.91.camel@kernel.crashing.org> (raw)

Hi !

I noticed that flow control isn't being enabled on a system I'm
working on by default. I've tracked it down to two things:

 - The realtec.c PHY driver doesn't have Pause or Asym_Pause in
its exposed capabilities. This is in part because PHY_GBIT_FEATURES
does not include SUPPORTED_Pause and SUPPORTED_Asym_Pause. Is there
a specific reason for that ?

 - After I've hacked the above, I get in genphy_read_status():

lpa=c1e1 lpagb=3800 adv=de1 common_adv=1e1 common_adv_gb=800

So we have negociated 1000bT full duplex. LPA_PAUSE's aren't set
but I was under the impression that in Gigabit mode, LPA bit 0x80
which *is* set, meant ADVERTISE_1000XPAUSE which is the pause
capability isn't it ? Or am I confusing with something else ?
This seems to be how mii_adv_to_ethtool_adv_x() decodes them
but that function is not called by genphy_read_status()...

Now it's been a while since I hacked network drivers and back then
everybody did their own salad with gigabit PHYs so it's very possible
that I missed something here.

Should we update genphy_read_status() to grab the pause details
from mii_adv_to_ethtool_adv_x() when in 1000bT mode ?

Thanks !

Cheers,
Ben.

             reply	other threads:[~2017-03-28  0:50 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-28  0:49 Benjamin Herrenschmidt [this message]
2017-03-28  1:09 ` genphy_read_status() vs. 1000bT Pause capability Andrew Lunn
2017-03-28  2:28   ` Benjamin Herrenschmidt
2017-03-28  2:55     ` Benjamin Herrenschmidt
2017-03-28  4:14       ` Florian Fainelli
     [not found]       ` <20170328041405.045FEB206B@b01ledav03.gho.pok.ibm.com>
2017-03-28  5:17         ` Benjamin Herrenschmidt
2017-03-28  5:19           ` Benjamin Herrenschmidt
2017-03-28  9:42           ` Russell King - ARM Linux
2017-03-28 11:11             ` Benjamin Herrenschmidt
2017-03-28 11:31               ` Russell King - ARM Linux
2017-03-28 20:32                 ` Benjamin Herrenschmidt

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