RE: SCSI QLA not working on latest *-mm SN2

Andrew Vasquez
2004-09-21T17:38:10Z

On , willy@www.linux.org.uk wrote:
>
> On Tue, Sep 21, 2004 at 08:58:23AM -0700, Andrew Vasquez wrote:
> > From what I can gather from the hw engineers, the config-read will
> > not guarantee a flush of posted writes.
>
> I believe your hardware engineers to be mistaken. See PCI 2.2,
> Appendix E, section E.2:
>
> 2. Memory writes can be posted in both directions in a bridge. I/O
> and Configuration writes are not posted. (I/O writes can be posted
> in the Host Bridge, but some restrictions apply.) Read transactions
> (Memory, I/O, or Configuration) are not posted.
>
> 5. A read transaction must push ahead of it through the bridge any
> posted writes originating on the same side of the bridge and posted
> before the read. Before the read transaction can complete on its
> originating bus, it must pull out of the bridge any posted writes
> that originated on the opposite side and were posted before the read
> command completes on the read-destination bus.
>

Hmm...adding more confusion to the mix. I apologize -- my reply was
not written correctly, yes, the config-read will flush any pending
writes. But, the same problem persists -- the RISC will still stop
responding to requests (config or MMIO) during the soft-reset --
potentially resulting in a MAC (as seen by SGI).

The 'safe' solution (as suggested by the hw people) was to use PIO to
issue the soft-reset, then udelay().

--
Andrew