Re: Stream Lined Booting - SCSI Hold Up

[Patrick Mansfield <patmans@us.ibm.com>]

On Wed, Jun 05, 2002 at 10:22:40AM -0700, Shane Walton wrote:
> Good day,
> 
> I work with US DoD systems, and one of my requirements
> is to boot an ix86 based system with an aic7xxx SCSI
> interface in 15 seconds.  One of the apparent problems
> is the SCSI BIOS and aic7xxx driver take a long time
> to find one drive and then probe other empty channels.
>  Is there a way to inform the aic7xxx driver of
> connected hardware to limit the initialization phase? 
> Thanks for the help.

I never thought to disable the reset, getting rid of the SCSI resets
probably cuts 10-20 seconds off my boot time.

You can turn of the AIC driver reset, and shorten the selection timeout,
see linux/drivers/scsi/README.aic7xxx for details.

With my hardware, I can also disable the BIOS reset, and limit BIOS
scanning from the BIOS config screen (hit ctl-A during boot).

On my system, it saves me about 10 seconds to boot with:

lilo: linux-1 aic7xxx=no_reset aic7xxx=seltime:3

There are no options in linux scsi to limit the scanning of the target
id's or channels, I don't think there are any in the AIC driver either.

You could hack the driver and lower the max_id, and/or lower max_channel,
or somehow disable unused channels, but I doubt it will save much time
(7 id's * 2 channels * 32 ms/per-selection-timeout or so).

-- Patrick Mansfield