Re: FIXED: mpt Serious performance issues

[Julian Coleman <jdc%coris.org.uk@localhost>]

Hi,

> This is approx. the maximum performance of the old hardware.
> 
>                                                                 When
> the computer starts, the LSI Firmware BIOS scans the disks and sets a
> meaningful initial setup for each of them.

> What then happens is very stupid. The driver calls
> mpt_set_initial_config() in mpt.c which resets every 16 target device
> pages to 0:

> Now every physical disk, being part of a RAID array or not, runs in a
> prehistoric mode. When the scsipi layer then scans the bus and detects
> the virtual target (sd0), the target device page for disk 0 again gets
> initialized with useful values (this is the fast, lower disk) but the
> page for disk 1 obviously not (this is the slow, upper disk). A simple
> but useful solution seems to be the removal of the code which clears
> all of the target pages as they were initialized correctly by the
> Firmware BIOS. A patch is attached. Comments? Is this good for
> commitment?

Very nice find!  I only wonder if there are cases where the firmware does
not correctly initialise the disks?  If so, we could initialise all disks
with useful values.  However, that might be seen as an enhancement to your
changes.

Thanks,

J

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