Messages in this thread | | | Date | Mon, 12 Feb 2007 16:57:35 +0100 (CET) | From | Geert Uytterhoeven <> | Subject | Re: NAK new drivers without proper power management? |
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On Mon, 12 Feb 2007, Pavel Machek wrote: > > > "If the device requires that, implement .suspend and .resume or at least > > ^^^^^^^^ > > > define .suspend that will always return -ENOSYS (then people will know they > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > have to unload the driver before the suspend). Similarly, if you aren't sure > > > whether or not the device requires .suspend and .resume, define .suspend that > > ^^^^^^^^^^^^^^^^^^^^ > > > will always return -ENOSYS." > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > Can't the upper layer just assume -ENOSYS if .resume/.suspend is NULL? > > It's nicer if you don't have to implement dummy functions at all. > > Unfortunately, drivers currently assume "NULL == nothing is needed", > so we'd have t do big search & replace...
Which means you also cannot easily keep track of which driver supports suspend/resume and which doesn't, as there will always be drivers where a missing suspend/resume function is correct.
Wouldn't it be more sensible to have
.suspend = suspend_nothing_to_do
instead, and reserve NULL for `not yet implemented'?
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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