Hello.
With the new RTM build 2180 of SP2 for Windows XP, we have noticed some
changes in the MS implemented 1394 stack. Specifically, we have observed
that the host controller node as managed by the MS 1394 stack is no longer
IRM capable. This is quite contrary as compared with Windows 2000 SP4,
Windows XP SP1a, and even Windows XP SP2 RC2 (build 2149). This would break
any 1394 product already on the market which uses isochronous I/O and is
itself not IRM capable. This is because (as you know) as per the 1394 spec
the IRM maintains certain registers for cooperative use over the firewire
network for isochronous I/O. These registers are mainly used for listing the
currently available channels and bandwidth. Without these registers, there
is no way for anyone on the firewire network to reliably engage in
isochronous I/O. Based on these observations, we were wondering:
a) What are the reasons behind this change? To see this large a change
introduced sometime after SP2 RC2 (build 2149) in SP2 RTM (build 2180) is
surprising to say the least.
b) We see that SP2 RC2 (build 2149) had IRM capability for the MS local
controller node. Is there any public interface available for enabling IRM
capability on the MS local controller node in build 2180 (RTM)?
c) Are there any workarounds for this issue?
d) Are any hotfixes planned to address this issue?
e) Will this new policy be extended to other Windows Operating Systems?
thank you,