Patchwork net: usb: smsc95xx: fix mtu

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Submitter Stephane Fillod
Date April 20, 2012, 7:39 p.m.
Message ID <20120420193923.GQ5277@charybde.local>
Download mbox | patch
Permalink /patch/154121/
State Accepted
Delegated to: David Miller
Headers show

Comments

Stephane Fillod - April 20, 2012, 7:39 p.m.
Make smsc95xx recalculate the hard_mtu after adjusting the
hard_header_len.

Without this, usbnet adjusts the MTU down to 1488 bytes, and the host is
unable to receive standard 1500-byte frames from the device.

Inspired by same fix on cdc_eem 78fb72f7936c01d5b426c03a691eca082b03f2b9.

Tested on ARM/Beagle.

Signed-off-by: Stephane Fillod <fillods@users.sf.net>
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David Miller - April 24, 2012, 4:29 a.m.
From: Stephane Fillod <fillods@users.sf.net>
Date: Fri, 20 Apr 2012 21:39:23 +0200

> Make smsc95xx recalculate the hard_mtu after adjusting the
> hard_header_len.
> 
> Without this, usbnet adjusts the MTU down to 1488 bytes, and the host is
> unable to receive standard 1500-byte frames from the device.
> 
> Inspired by same fix on cdc_eem 78fb72f7936c01d5b426c03a691eca082b03f2b9.
> 
> Tested on ARM/Beagle.
> 
> Signed-off-by: Stephane Fillod <fillods@users.sf.net>

Applied, thanks.

Ok, now we've made this fix to 2 or 3 USB net drivers, can someone
audit to see if any more remain?
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Patch

--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1016,6 +1016,7 @@ 
 	dev->net->ethtool_ops = &smsc95xx_ethtool_ops;
 	dev->net->flags |= IFF_MULTICAST;
 	dev->net->hard_header_len += SMSC95XX_TX_OVERHEAD_CSUM;
+	dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
 	return 0;
 }