From: Andrew Lunn <andrew@lunn.ch>
To: Tristram.Ha@microchip.com
Cc: pavel@ucw.cz, f.fainelli@gmail.com, UNGLinuxDriver@microchip.com,
netdev@vger.kernel.org
Subject: Re: [PATCH RFC 5/6] net: dsa: microchip: Update tag_ksz.c to access switch driver
Date: Wed, 12 Dec 2018 09:18:41 +0100 [thread overview]
Message-ID: <20181212081841.GA28679@lunn.ch> (raw)
In-Reply-To: <SN1PR11MB0446BF515D324351DCA56067ECA60@SN1PR11MB0446.namprd11.prod.outlook.com>
On Tue, Dec 11, 2018 at 11:59:34PM +0000, Tristram.Ha@microchip.com wrote:
> > I'd be careful about locking. Seems like dsa was designed with "tag
> > format is static", and you want to change it dynamically...
>
> I see there is now a new overhead parameter in the dsa_device_ops structure
> and dev_set_mtu is called in master.c. It does not prevent the tag size to
> change dynamically though. A bigger size can be used instead to make sure the
> MAC controller can support it.
>
> In practice I do not think it does anything meaningful. Most MAC controllers
> can transmit and receive more than 1518 bytes but still only advertise 1500
> MTU.
Hi Tristram
There are a few MAC devices to do enforce 1518. e1000e is one
example. You have to increase the MTU before it will receive DSA
tagged frames. I initially had similar problems with the FEC driver
when i started using that a few years ago. At that time i did not
rallies it was a wide scale problem and just changed the FEC. This
should be a more generic solution.
Andrew
next prev parent reply other threads:[~2018-12-12 8:18 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-03 23:34 [PATCH RFC 0/6] net: dsa: microchip: Modify KSZ9477 DSA driver to support different tail tag formats Tristram.Ha
2018-12-03 23:34 ` [PATCH RFC 1/6] net: dsa: microchip: Prepare PHY for proper advertisement Tristram.Ha
2018-12-05 17:40 ` Andrew Lunn
2018-12-06 20:31 ` Tristram.Ha
2018-12-03 23:34 ` [PATCH RFC 2/6] net: dsa: microchip: Add MIB counter reading support Tristram.Ha
2018-12-05 17:53 ` Andrew Lunn
2018-12-06 20:16 ` Tristram.Ha
2018-12-06 20:42 ` Andrew Lunn
2018-12-03 23:34 ` [PATCH RFC 3/6] net: dsa: microchip: Break ksz_priv.h into two files Tristram.Ha
2018-12-03 23:34 ` [PATCH RFC 4/6] net: dsa: microchip: Each switch driver has its own tail tagging operations Tristram.Ha
2018-12-03 23:34 ` [PATCH RFC 5/6] net: dsa: microchip: Update tag_ksz.c to access switch driver Tristram.Ha
2018-12-05 18:00 ` Andrew Lunn
2018-12-05 18:18 ` Andrew Lunn
2018-12-05 18:52 ` Florian Fainelli
2018-12-06 20:00 ` Tristram.Ha
2018-12-06 20:41 ` Andrew Lunn
2018-12-07 3:16 ` Richard Cochran
2018-12-09 9:17 ` Pavel Machek
2018-12-11 23:59 ` Tristram.Ha
2018-12-12 8:18 ` Andrew Lunn [this message]
2018-12-03 23:34 ` [PATCH RFC 6/6] net: dsa: microchip: Add switch offload forwarding support Tristram.Ha
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