Re: [PATCH net,stable] cdc_ncm: workaround for EM7455 "silent" data interface

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Oliver Neukum <oneukum@xxxxxxxx> writes:
> On Sun, 2016-07-03 at 22:24 +0200, Bjørn Mork wrote:
>> Several Lenovo users have reported problems with their Sierra
>> Wireless EM7455 modem. The driver has loaded successfully and
>> the MBIM management channel has appeared to work, including
>> establishing a connection to the mobile network. But no frames
>> have been received over the data interface.
>
> If this is needed in open() it must also be needed in reset_resume()

reset_resume needs fixing in general. This is completely unrelated to
this bug. In fact, as we don't do any NCM control messages there in the
current resume, I'm not sure this firmware bug is triggered by it.  But
it's untestable, because:

reset_resume cannot work for MBIM. At least not with the driver/userspace
model we have chosen.  The driver does not have enough information about
the device state to recreate it.  It could maybe work for NCM, but I
don't think it currently does.  The NCM protocol requires some minimum
driver and device negotiation, and the current NCM .reset_resume points
to usbnet_resume which completely ignores that.

Proposals for fixing reset_resume would of course be good, and I'll
think about how to deal with it, but I don't think it should block
fixing the current issue.  They are not related.


Bjørn
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux