Cycling '74 Max MSP crashes when selecting a 22050 Hz sample rate

[dechamps]

With FlexASIO 1.5, using the default configuration, Max 8.1.5 violently crashes when attempting to select a 22050 Hz sample rate on FlexASIO.

The FlexASIO log ends with the following:

--- ENTERING CONTEXT: getBufferSize()
Calculating default buffer size based on 22050 Hz sample rate
Returning: min buffer size 22, max buffer size 22050, preferred buffer size 441, granularity 1
--- EXITING CONTEXT: getBufferSize() [OK]

A debugger reveals that Max is crashing in some kind of stack in ad_asio!ext_main, and seems to be passing an invalid pointer to sscanf(). FlexASIO does not appear anywhere in the crashing stack.

Setting bufferSizeSample = 128 gets rid of the issue. It looks like Max is choking on the buffer sizes that FlexASIO advertises by default.

[dechamps]

This crash can also be triggered by Max falling back to the first available sample rate (which is typically 22050 Hz) for whatever reason, which can happen when the Max user settings don't match the underlying capabilities. In that case the only way to recover is to reset the settings (in AppData\Roaming\Cycling '74).

[dechamps]

Upon further investigation, appears that Max crashes if the driver reports a minimum buffer size of 31 samples or less. 32 samples or more is fine.

[dechamps]

This is fixed in FlexASIO 1.6 by enforcing a 32-sample lower limit on the default minimum buffer size.