[alsa-devel] ALSA Control Questions (atomicity, error handling)

Clemens Ladisch clemens at ladisch.de
Fri Dec 4 13:33:17 CET 2009

Tobias Schneider wrote:
> Another point: I figured out that the "ALSA middlelayer" seems to filter
> the given values of a control. So if the user sets value=1000 where
> maximum is 10, I will get 10 instead of 1000 in the put callback...so
> it's not necessary to check values in those callbacks,

It is, because it is possible to use low-level ALSA functions or to call
the IOCTLs directly, and in this way arbitrary values can reach your
driver's put callback.

Best regards,

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