Re: [PATCH] aic79xx should be able to ignore HostRAID enabled adapters

Heinz Mauelshagen
2005-12-01T14:48:28Z

On Thu, Dec 01, 2005 at 08:44:15AM -0500, Salyzyn, Mark wrote:
> Christoph Hellwig sez:
> > NACK. We're not going to support attaching broken propritary drivers.
>
> Understood and expected.
>
> The word 'broken' is hardly chosen for scientific reasons, bespeaks an
> agenda ;-> Just because you can not see the code, does not mean it is
> broken.
>
> I have on numerous attempts tried to contact Heinz Mauelshagen to
> fortify dmraid in support of the HostRAID adapters. He has yet to
> respond to my emails to start a dialogue with Adaptec.

None of those here.
Please forward.

>
> Justin Gibbs had provided the community the emd driver, soundly rejected
> and never ported to dm because there were features that Justin held dear
> in md that do not translate to dm. An unfortunate waste of considerable
> resources.
>
> Without the timely agenda and cooled temperaments to close the gap, the
> solution should be temporarily to support the proprietary HostRAID
> driver when the Adapter is in HostRAID mode and we continue to work to
> close that gap on dmraid.
>
> Could you agree with that to help the users today?
>
> [ You are on record as not giving a fig for the users, what if I showed
> them as starving children in a third world nation, would that melt your
> heart? ;-} ]
>
> > Sepcially as these "HostRAID" cards are plain SCSI HBAs.
>
> They are plain SCSI HBAs, but are designated as a RAID card rather than
> a Host Bus Adapter in the PCI config space when in 'HostRAID' mode. The
> fact that is designated in the PCI space should be enough reason *not*
> to attach a simplified LLD.
>
> The HostRAID driver has a specialized (ok, yes, also proprietary) CHIM
> and sequencer where attention can be focused on techniques of
> performance improvement and OS agnostics. In addition, the RAID code in
> that driver understands the hardware, CHIM & sequencer and takes
> advantage of features that just can not be performed by an abstracted dm
> or an LLD. RAID1 is handled under some conditions, for instance, with
> one DMA operation over the PCI bus rather than two duplicated for each
> target, greatly increasing the performance.
>
> Linux is not about performance first, it is about doing it the Linux
> way. I believe we can understand that. And in turn, do not consider it
> harmful if a group of individuals trying to make a living see a chance
> to acquire a competitive edge.
>
> Sincerely -- Mark Salyzyn

--

Regards,
Heinz -- The LVM Guy --

*** Software bugs are stupid.
Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen Red Hat GmbH
Consulting Development Engineer Am Sonnenhang 11
Cluster and Storage Development 56242 Marienrachdorf
Germany
Mauelshagen@RedHat.com +49 2626 141200
FAX 924446
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