Re: SO_TIMESTAMPING fix and design decisions

[Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>]

On Sun, 2009-09-20 at 00:52 -0700, Christopher Zimmermann wrote:
> On Sat, 19 Sep 2009 15:09:21 -0700
> Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com> wrote:
> 
> > > hardware timestamps only work for the Intel igb driver. I have 
> > > access to two test machines with NICs supported by this driver.
> > 
> > Intel's 82599, supported by ixgbe, also has the same IEEE 1588
> > timestamping support in hardware.  We haven't implemented the support
> > yet in ixgbe, but the hardware is there and does work.  If you were
> > curious of the interface, the datasheet for the hardware is available on
> > our SourceForge site (e1000.sf.net).
> 
> hi! thanks for the reply.
> 
> I already got the documentation for the 82576 cards I have access to. I 
> won't be able to afford another pair.
> 
> What do you think about my idea to expose the relevant registers to 
> userspace? I believe it would not be too difficult for userspace to 
> configure the timestamps this way and would allow way more flexibility. 
> Of course I would #DEFINE the constants used to set the registers.

The patch seems reasonable, but I haven't played with the igb
timestamping very much.  However, what impact will this have on the
existing ptpd userspace daemon?

-PJ