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From: Sam Bingner <>
To: "" <>
Cc: "David S. Miller" <>,
	Martin Habets <>,
	Luc Van Oostenryck <>,
	Shannon Nelson <>,
	"Michael S. Tsirkin" <>,
	"" <>,
	"" <>,
	Matti Vuorela <>,
	Jakub Kicinski <>,
	"Yves-Alexis Perez" <>
Subject: Re: [PATCH] usbnet: ipheth: fix connectivity with iOS 14
Date: Sun, 21 Feb 2021 10:42:44 +0000
Message-ID: <> (raw)

There seems to be a problem with this patch:

Whenever the iPhone sends a packet to the tethered device that is 1500 bytes long, it gets the error "ipheth 1-1:4.2: ipheth_rcvbulk_callback: urb status: -79" on the connected device and stops passing traffic.  I am able to bring it back up by shutting and unshutting the interface, but the same thing happens very quickly.   I noticed that this patch dropped the max USB packet size from 1516 to 1514 bytes, so I decided to try lowering the MTU to 1498; this made the connection reliable and no more errors occurred.

It appears to me that the iPhone is still sending out 1516 bytes over USB for a 1500 byte packet and this patch makes USB abort when that happens?  I could duplicate reliably by sending a ping from the iphone (ping -s 1472) to the connected device, or vice versa as the reply would then break it.

I apologize if this reply doesn't end up where it should - I tried to reply to the last message in this thread but I wasn't actually *on* the thread so I had to just build it as much as possible myself.


             reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-21 10:42 Sam Bingner [this message]
2021-02-22 12:09 ` Oliver Neukum
  -- strict thread matches above, loose matches on Subject: below --
2020-09-27 14:14 /net/usb/ipheth.c incompatibility with Apple " Kiran
2020-11-19 17:24 ` [PATCH] usbnet: ipheth: fix connectivity with " Yves-Alexis Perez
2020-11-20  9:15   ` Sergei Shtylyov
2020-11-20 16:56     ` Yves-Alexis Perez
2020-11-21 22:03   ` Jakub Kicinski
2020-11-24 10:41     ` Yves-Alexis Perez
2020-11-24 16:39       ` Jakub Kicinski

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