RE: [rft]aggressive autosuspend for cdc-ether

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Hi Oliver,
thanks for the speedy answer! I'll try to do as you suggest and report
on progress later. Hopefully some time tomorrow!

Regards,
Greg.

-----Original Message-----
From: Oliver Neukum [mailto:oliver@xxxxxxxxxx] 
Sent: 09 September 2009 16:55
To: Greg Heinrich
Cc: Nicolas Chevillot; David Brownell; linux-usb@xxxxxxxxxxxxxxx; Carl
Nordbeck
Subject: Re: [rft]aggressive autosuspend for cdc-ether

Am Mittwoch, 9. September 2009 15:21:33 schrieb Greg Heinrich:

Hi,

> I have been playing with your cdc-ether patch for autosuspend. This is
> mostly working however I have experienced some issues especially when
> autosuspend is enabled before the cdc-ether virtual cable is
connected.
> In that case, the host usually fails to get an IP address from the
DHCP
> server. Sometimes it works, most of the times it doesn't. I have not
yet
> managed to understand what makes it fail/succeed.

Please recompile your kernel with CONFIG_USB_DEBUG.
This will increase debugging. It sounds like this happens if
the device is suspended when the dhcp request should be done.
But while this is very likely we need to confirm it.

> I collected wireshark logs a few of the failing cases and it turns out
> that the host does not send any DHCP_Discovery packets over the
> cdc-ether interface. There are no obvious errors in the kernel logs.

If nothing is sent, wireshark won't help. Verbosity of kernel logging
must be increased. If CONFIG_USB_DEBUG doesn't do the job,
you'll have to remove the comments from these lines

// #define	DEBUG			// error path messages, extra
info
// #define	VERBOSE			// more; success messages

in drivers/net/usb/usbnet.c

> Am I using your patch beyond its intended use, or doing anything
wrong?

Nope, this has to work. You've found a bug. ;-)

	Regards
		Oliver


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