RE: [RFC] ethtool: Display reg dump length via get driver info.

On Fri, 2011-03-18 at 14:52 -0700, Ajit.Khaparde@Emulex.Com wrote:

______________________________________
From: Ben Hutchings [bhutchings@solarflare.com]
Sent: Friday, March 18, 2011 4:32 PM
To: Khaparde, Ajit
Cc: netdev@vger.kernel.org
Subject: Re: [RFC] ethtool: Display reg dump length via get driver info.

On Fri, 2011-03-18 at 16:06 -0500, Ajit Khaparde wrote:

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Devices like BE store Reg Dump Data in the hardware.

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Where else would it be?

Well yes. That's true.

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This change will allow to just peek into the hardware
to see if any data is available for a dump and analysis,
without actually dumping the register data.

[...]

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This is wrong.  ethtool_ops::get_regs_len really should return a
constant, otherwise ethtool (and the kernel) cannot allocate a buffer of
the right size.  If the size of a dump really does vary then make it
return the maximum possible size for the device.

Yes, it is a constant size. And will always be the max size possible.
I just want to see if I can get the length, without really making the ethtoool -d call.
Because that will trigger the dump too.
At that moment, I may not be interested in the data itself.

OK, so what you're really interested in is 'does this version of the
driver support register dump'?

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.