* Viresh Kumar <viresh.ku...@linaro.org> wrote:
> > So why is a 'default' mode needed then? It makes the
> > addition of new modes to the legacy handler easier,
> > which looks backwards.
>
> The requirement was to add another mode ONESHOT_STOPPED
> [1], to be supported only by the new per-mode callbacks..
Why would a callback need any flag, and why would a flag be
visible to old legacy callbacks?
> We have got a clear check in core with the patch Peter
> mentioned above, which doesn't let us call legacy
> ->set_mode() for the newer modes.
>
> if (dev->set_mode) {
> /* Legacy callback doesn't support new modes */
> if (mode > CLOCK_EVT_MODE_RESUME)
> return -ENOSYS;
> dev->set_mode(mode, dev);
> return 0;
> }
So here is where one of your problems comes from: why did
you add CLOCK_EVT_MODE_RESUME to the interface? Phase it
out, it's a legacy interface - new callbacks shouldn't need
any mode flags to begin with.
> > So I'm confused: if we are using proper callbacks (like
> > my example outlined) , why is a 'mode enum' needed at
> > all?
>
> The enum has two uses today:
>
> - pass mode to the legacy ->set_mode() callback, which
> isn't required for the new callbacks.
But this is misguided, as per above.
> - flag for clockevent core's internal state machine,
> which it would still require. For example, it checks
> new-mode != old-mode before changing the mode..
Internal state machine state should be decoupled from any
interface flags - especially when the interface is legacy.
> I believe the enum is still required for the state
> machine, even with new per-mode callbacks.
That needs to be fixed first then, before introducing new
API variants.
Thanks,
Ingo
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