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Date:      Tue, 26 Feb 2008 10:03:34 +0900
From:      Pyun YongHyeon <pyunyh@gmail.com>
To:        Sharad Chandra <sharadc@in.niksun.com>
Cc:        freebsd-drivers@freebsd.org
Subject:   Re: Start Fire nic card.
Message-ID:  <20080226010334.GA47750@cdnetworks.co.kr>
In-Reply-To: <200802251443.00541.sharadc@in.niksun.com>
References:  <200802251443.00541.sharadc@in.niksun.com>

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On Mon, Feb 25, 2008 at 02:43:00PM +0530, Sharad Chandra wrote:
 > Hi,
 > 
 > ????????How does dual port star fire nic card time stamps? Is the sheduling 
 > round robin. if it is, there can be chances, a frame comes later than other 
 > can get lesser timestamp.
 > 

The Adaptec AIC-6915(aka StarFire) supports timestamps in its
Tx/Rx descriptor format. So you can get a timestamp for each
transmitted/received frames. The timestamp is based on an internal
32bit CurrentTimer register(0.8us resolution).
ATM sf(4) does not use these timestamps in descriptor format so
you have to change decriptor format to include the timestamp and
initialize CurrentTimer register prior to get timestamps.
But there is no easy to pass these timestamp information to upper
layer so you may have to add special ioctls into the driver to get
these information. See Adaptec AIC-6915 datasheet for more
information.
In order to get correct timestamp on Dual/Quad ports Starfire NICs
you may have to to set CurrentTimer register of all ports with the
same value to synchronize the timer value.

-- 
Regards,
Pyun YongHyeon



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