Patch RFC: Promise SATA300 TX4 hardware bug workaround.

[Roman Kurakin]

By the way, is there any chance to get RAID5 working with this controller?

rik

Alexander Sabourenkov wrote:
> Arno J. Klaassen wrote:
>   
>> Rather than the marginal HW part, it seems, for me, closely related to
>> MB/BIOS (as well (Alexander apperently has about the same setup as I
>> have for this test)):
>>
>>     
>
> [...]
>
>   
>> I vaguely remember from another PR that the Promise card does
>> something with PCI-bursting which fbsd does not detect and/or
>> handle correctly (and beyond my simple skills as dumb tester, but
>> maybe the linux-sources contain a clue about that as well).
>>
>>     
>
> Analysis of chip initialization in vendor-supplied, Linux and FreeBSD
> drivers shows that FreeBSD's one:
> - does not enable something called 'BMR_BURST',
> - performs hotplug init in one write (instead of two read-modify-writes ),
> - does an extra write (offset 0x54) which is not done in other drivers.
>
> Analysis text: http://lxnt.info/tx4/chipinit.text
>
> Patch with ported chipinit (dangerous to use with anything from Promise
> other than sata300 tx4 !!):
> http://lxnt.info/tx4/freebsd/chipinit.patch (cumulative)
> http://lxnt.info/tx4/freebsd/ata-chipset.c+chipinit (patched source)
>
> Note two things:
> 1. I have not compiled or tested this patch. Please do.
> 2. I may have missed this bug because I'm frequently rebooting between
> Linux and FreeBSD, and what Linux driver initialized may have lasted the
> reboots.
>
>
>