From: Luben Tuikov <luben_tuikov@adaptec.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "Moore, Eric Dean" <Eric.Moore@lsil.com>,
jejb@steeleye.com, linux-scsi@vger.kernel.org
Subject: Re: [PATCH 1/4] sas: add flag for locally attached PHYs
Date: Thu, 20 Oct 2005 12:08:24 -0400 [thread overview]
Message-ID: <4357C0F8.3030400@adaptec.com> (raw)
In-Reply-To: <20051020154942.GA12809@lst.de>
On 10/20/05 11:49, Christoph Hellwig wrote:
> <lots of useless rants snipped>
Hi Christoph,
For some reason I thought that I was quoting specs
and showing constructive ideas (i.e. things you can sit down
and start coding).
I'm sorry that you feel that it is "useless rants".
On a topic note: It appears that the "sas transport attributes" are
nothing more than SDI/CSMI.
> Yes, we have two cases, local phy and phy on an expander. The proper
> way to support remote phys is via smp passthru as we hopefully agree.
> Right now the sas transport class doesn't do smp passthru (although
> I'm working on it) so we only implement local link stats.
You are so much better off implementing SDI/CSMI as per the spec.
Normally, at companies, projects have a "specificaion" and "required
functionality". What is the "specificaion" and "required functionality"
at hand?
Note that there are LSI/HP customers who are completely _happy_
to use CSMI as provided by LSI and they are not interested in
what-have-you-not.
The easiest way to make those customers happy and keep them happy is
to provide general SDI/CSMI facitliy and _you have a spec on that_.
> Once we have
> smp passthru we can support link stats, in one of two ways:
>
> - do it in userland as in your example program. in that case we don't
> need to do anything in kernel land and need the local_attached flag
> to disable this functionality for expander phys.
> - do it in kernel, in which case the transport class must call the smp
> passthru entry point of the driver to query link stats, so it needs
> the local_attached flag aswell for that.
>
> What's your problem with the flag now?
It is ugly, it is a (brown) paper bag solution, it is a work around.
Take a look at the phy attributes as per the SAS spec. Then take
a look at struct sas_phy in include/scsi/sas/sas_class.h. Do you
see such a flag in either reference?
Luben
--
http://linux.adaptec.com/sas/
http://www.adaptec.com/sas/
next prev parent reply other threads:[~2005-10-20 16:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-19 20:08 [PATCH 1/4] sas: add flag for locally attached PHYs Moore, Eric Dean
2005-10-19 21:00 ` Luben Tuikov
2005-10-20 14:11 ` Christoph Hellwig
2005-10-20 15:29 ` Luben Tuikov
2005-10-20 15:49 ` Christoph Hellwig
2005-10-20 16:08 ` Luben Tuikov [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-10-20 15:45 Moore, Eric Dean
2005-10-20 16:16 ` Luben Tuikov
2005-10-20 15:25 Moore, Eric Dean
2005-10-20 15:55 ` Luben Tuikov
2005-10-20 16:01 ` Christoph Hellwig
2005-10-20 16:51 ` Luben Tuikov
2005-10-20 17:03 ` Christoph Hellwig
2005-10-20 17:22 ` Arjan van de Ven
2005-10-20 20:10 ` Luben Tuikov
2005-10-21 8:16 ` Arjan van de Ven
2005-10-20 20:02 ` Luben Tuikov
2005-10-21 0:01 ` Andrew Patterson
2005-10-21 9:06 ` Arjan van de Ven
2005-10-21 17:05 ` Andrew Patterson
2005-10-21 17:18 ` Arjan van de Ven
2005-10-21 18:57 ` Luben Tuikov
2005-10-21 17:32 ` Luben Tuikov
2005-10-21 1:50 ` Douglas Gilbert
2005-10-21 2:16 ` Jeff Garzik
2005-10-21 3:25 ` Douglas Gilbert
2005-10-21 18:04 ` Luben Tuikov
2005-10-19 18:01 Christoph Hellwig
2005-10-19 19:24 ` Luben Tuikov
2005-10-19 19:37 ` Luben Tuikov
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