Any successful installs on a Broadcom HT1000 chipset?

[Travis Mikalson]

Søren Schmidt wrote:
> 
> OK, so I found at least one problem with the HT1000, its sometimes 
> doesn't handle 128 sector transfers correctly, its DMA engine looses its 
> wits.
> The result is that it just messes up completely and barfs data all over 
> the place on the next read operation.
> 
> Anyhow the attached patch seems to work around the problem by limitting 
> transfer to a max of 126 sectors in one go, at least I have move several 
> hundred Gb's around now on a zfs volume without problems, which 
> certainly wasn't possible before.
> 
> Let me know how this turns out for you!
> 
> Patch is against a clean RELENG_7 as last time, should fit both RELENG_6 
> and -current...

You definitely found the trouble area.

This patch allows me to boot and use my Tyan on-board SATA controller 
without any errors or memory corruption.

As an aside, this patch breaks dumping. The disk device (ad6) complains 
about an oversized DMA and fails to dump on panic now. (No, your patch 
hasn't created any new panics or anything, btw...)

So this is a successful workaround for the HT1000 on-board SATA, and it 
looks like this additional workaround you just posted is pretty 
universal and would also limit a Marvell PCI-X SATA controller's DMA size.

Do you suppose there will be some way to make this workaround more 
"global" so that in the presence of an HT1000 chipset, everything (not 
just ata) will avoid trying large DMA transfers and thus triggering the bug?

I don't suppose you think ServerWorks/Broadcom would care to help 
comment on what might be a more proper global fix-all for this issue...

I think it could really save some people with this hardware some trouble 
if an HT1000 workaround made it into 7.0-RELEASE. Without your fix, if 
someone afflicted by this HT1000 problem booted up 7.0 it would start 
corrupting their existing data and there could be some major crying at 
some point down the road :)

Thanks for your work, good job finding it!
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