Deal with 'NotOpened' errors?
bjorn at mork.no
Mon Feb 24 09:08:25 PST 2014
Dan Williams <dcbw at redhat.com> writes:
> On Mon, 2014-02-24 at 14:47 +0100, Bjørn Mork wrote:
>> Aleksander Morgado <aleksander at aleksander.es> writes:
>> > Just re-opening the MBIM port is not enough very
>> > likely as we would need to re-send PIN at least... If we detect this,
>> > we should likely mark the modem as invalid and re-start probing from
>> > scratch, so that we keep a sane state within MM.
>> Yes. This seems pretty straight forward for MBIM modems, where
>> NotOpened will mean that everything must be reinitialized.
>> But I guess similar issues will affect all types of USB attached modems.
>> So MM should really handle "modem amnesia" regardless of modem driver.
>> If USB power is removed and the USB core decides to apply the "persist
>> feature", then you will see this as a modem forgetting every volatile
>> configuration command you have sent it.
> Perhaps the kernel provides some kind of "we're suspending now" signal
> that MM can use to selectively invalidate modems. But I'm not sure it
> does, as all that appears to currently be handled in userspace with
> stuff like pm-utils, upower, or systemd. We could track the monotonic
> timer by setting up a 2 or 3 second poll and see if it changes *more*
> than 2 or 3 seconds, but that's a hack.
Making MM aware of PM actions is unnecessary complicated. Dealing with
unexpected errors instead of ignoring them should be sufficient. Or?
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