Re: [PATCH 2/2] thinkpad_acpi: Hook volume events

[Matthew Garrett <mjg59@srcf.ucam.org>]

On Wed, May 05, 2010 at 08:30:05AM -0300, Henrique de Moraes Holschuh wrote:

> The idea is sound, but it would be probably cleaner to do it only on those
> thinkpads which need it.  I don't like the idea of handling duplicate
> notifications, and the logic depends entirely on nothing messing with the
> mixer state behind our backs, I'd prefer to rely on it just when strictly
> required.

In this case the notification is purely at the ALSA level, so there's no 
harm caused by duplicate notifications.

> Also, UCMS is called for a number of reasons.  It would be best to filter
> based on the UCMS parameter before doing an expensive PC CMOS RAM read or EC
> read.  We will be dealing with a finite number of thinkpads anyway.

Passing the parameter is... difficult. That would involve rather more 
surgery to the ACPI core, since the parameters are core-internal objects 
at this point. It's an obvious feature though, so I'll look into it some 
more.

> On the same note, we need to be called *after* the UCMS method completes,
> otherwise, we will have to schedule delayed work.  I didn't study your ACPI
> patch enough to know whether this happens, but that detail is not clear from
> the description.

The call is made after executing the original method, yes.

-- 
Matthew Garrett | mjg59@srcf.ucam.org