Re: [PATCH update] ieee1394: cycle timer read extension for raw1394/libraw1394

From: Pieter Palmers
Date: Sat Feb 03 2007 - 09:27:24 EST


Stefan Richter wrote:
From: Pieter Palmers <pieterp@xxxxxxx>

This implements the simultaneous read of the isochronous cycle timer and
the system clock (in usecs). This allows to express the exact receive
time of an ISO packet as a system time with microsecond accuracy.
http://bugzilla.kernel.org/show_bug.cgi?id=7773

The counterpart patch for libraw1394 can be found at
http://thread.gmane.org/gmane.linux.kernel.firewire.devel/8934

Patch update (Stefan R.):
- Disable preemption and local interrupts.
- Fix integer overflow.
I had to use 1000000ULL instead of USEC_PER_SEC to avoid weird behavior.

- Add paranoid error checks and kerneldoc to hpsb_read_cycle_timer.
Move it to other ieee1394_core high-level API functions.
- Rename userspace-exported struct _raw1394_cycle_timer to
raw1394_cycle_timer. Change comments in raw1394.
- Adjust whitespace.
Thanks for the cleanups!

I can't test it right now, but I'll report later.

Pieter
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