From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Bottomley <James.Bottomley@HansenPartnership.com>
Subject: Re: [PATCH] mvsas: fix default can_queue
Date: Fri, 07 Mar 2008 09:03:05 -0600
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To: Ke Wei <kewei.mv@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>, linux-scsi <linux-scsi@vger.kernel.org>

On Fri, 2008-03-07 at 18:50 +0800, Ke Wei wrote:
> On a system with many SAS targets,  It appears possible that a
> scsi_cmnd can time out without ever making it to the SAS LLDD or at
> the same time that a completion is occurring.
> in file sas_scsi_host.c :
>                /* Queue up, Direct Mode or Task Collector Mode. */
>                if (sas_ha->lldd_max_execute_num < 2)
>                                res = i->dft->lldd_execute_task(task,
> 1, GFP_ATOMIC);
>                else
>                                res = sas_queue_up(task);
> If I set lldd_max_execute_num above 1, I find that libsas couldn't
> queue a task to the SAS LLDD sometimes.
> System will always report: not at initiator: EH_RESET_TIMER.
> Is queue_thread pending? I will keep investigating.

Oh, actually, that's the old task collector mode.  I keep meaning to
strip it out of libsas ... this provides a good excuse.  Basically the
only valid case is lldd_max_execute_num == 1 since, as you found,
anything above that doesn't work.

Are you still seeing timeouts in the lldd_max_execute_num == 1 case?
And if so, is that still with can_queue == 1?

James