ALSA: dice: improve support for ancient firmware for DICE
In early stage of firmware SDK, DICE seems to lose its backward
compatibility due to some registers on global address section. I found
this with Alesis Multimix 12 FireWire with ancient firmware (approx.
shipped version).
According to retrieved log from the unit, global section has 96 byte
space. On the other hand, current version of ALSA dice driver assumes
that all of supported unit has at least 100 byte space.
This commit adds support for the ancient firmware. Check of global section
is loosened to accept the smaller space. The lack of information is
already compensated by hard-coded parameters.
I experienced that the latest version of Windows driver for this model
can't handle this unit, too. This means that TCAT releases firmware SDK
without backward compatibility for the ancient firmware.
Below list is a early history of driver/firmware package released by
Alesis. I investigated on wayback machine on Internet Archive:
* Unknown: PAL v1.0.41.2, firmware v1.0.3
* Mar 2006: PAL v1.54.0, firmware v1.0.4
* Dec 2006: PAL v2.0.0.2, firmware v2.0
* Jun 2007: PAL v3.0.41.5, firmware v2.0
* Jul 2007: PAL v3.0.56.2. firmware v2.0
* Jan 2008: PAL v3.0.81.1080, firmware v2.0
If I can assume that firmware version is the same as DICE version, DICE
version for the issued firmware may be v1.0.3. According to code base of
userspace driver project (FFADO), I can read DICE v1.0.4 supports global
space larger than 100 byte. I guess the smaller space of global section is
a feature of DICE v1.0.3.