error codes for suspended printers
Oliver Neukum
oliver at neukum.name
Wed Oct 4 23:57:55 PDT 2006
Michael Sweet wrote:
> Oliver Neukum wrote:
>> Hi,
>>
>> I am implementing power management for usb printers in the kernel.
>> Which error code should be returned if CUPS tries to write to a suspended
>> printer?
>
> ENODEV would work with the current USB backend that uses the printer
> character device - that would trigger the automatic retry after a
> certain amount of time. The kernel would need to wake the printer
> up, however.
Thank you. ENODEV it shall be.
> That said, USB backend development on Linux is moving towards the
> user-mode USB API, so you might want to look at STR #1575 and build
> on that:
Unfortunately, on the kernel side, we cannot simply drop support
for usblp and we want it to do something sensible upon suspend.
Regards
Oliver
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