[Xenomai-core] Analogy regressions in xenomai 2.5.5.1

[Daniele Nicolodi <daniele@domain.hid>]

Hello, I just installed xenomai 2.5.5 on a 2.6.35.7 kernel and I'm
noticing serious regressions on analogy basic features:

1. Buffer management is badly broken. It is not possible to run any
acquisition command that wraps around in the ring buffer. That can be
simply reproduced with:

cmd_read -v d analogy0 -s 0 -S 0

after a while it will fail with: "cmd_read: a4l_read failed (ret=-32)".
In dmesg the driver reports: "Analogy: MITE: DME overwrite of free area".

2. Buffer is kept memory mapped after the mapping process dies. If a
process mapping a device buffer dies before un-mapping the buffer, it is
not possible to reconfigure the bnuffer. a4l_set_bufsize fails with
error code 32 and dmesg read "Analogy: a4l_ioctl_bufcfg: please unmap
before configuring buffer". Sinche the mapping process died I do not
know how to do this.

When I proposed some easy changes to the analogy API, to make it much
less confusing with trivial changes, Alexis expressed concerns about API
stability. What about functional stability? I think the reported ones
are major problems easily catch with simple pre-release tests...

Cheers,
Daniele