On Tue, Mar 5, 2013 at 8:50 PM, Oliver Neukum [off-list ref] wrote:

quoted

IMO, for autosuspend, that is right, but it is not for system suspend,
and the driver's suspend callback can't return in resumed state
because the USB core will ignore the failure return value and force
to suspend the device.

It seems to me that in this case you just need to make sure that
suspend() not fail for system suspend. Or revisit the decision to
ignore failures.

IMO, the current policy is correct.

In other words, if we don't handle errors, there must be no errors,
otherwise it doesn't matter what we do in the error case. We'd leave
the problem to generic layers.

Generic layers can't handle the driver's specific failure.

If driver records its suspend failure state in suspend(), resume()
should and can deal with it without much difficulty.

Furthermore there is a small chance that although the device tree
is walked, teh system suspend fails for another later reason that
is not ignored. In that case the drivers need to do error recovery,
albeit in resume().

Yes,  resume() need to handle the USB system suspend failure
either in normal resume or error recovery, both are basically same.

Thanks,
--
Ming Lei
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