From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel <qemu-devel@nongnu.org>,
ronnie sahlberg <ronniesahlberg@gmail.com>
Subject: Re: [Qemu-devel] scsi-generic and max request size
Date: Wed, 22 Dec 2010 14:27:10 +0100 [thread overview]
Message-ID: <20101222132710.GA8289@lst.de> (raw)
In-Reply-To: <4D12032E.6040602@suse.de>
On Wed, Dec 22, 2010 at 02:54:54PM +0100, Hannes Reinecke wrote:
> Most modern HBAs are using separate codepaths for streaming/block I/O
> anyway,
That's not true at all. Every normal HBA justs passes normal SCSI
commands to the SCSI targets. It's just raid adapters that take special
commands, and the megaraid one is extremly special as it actually
emulates a few SCSI commands even in RAID mode, which almost no other
HBA does. Strictly speaking we should not allow scsi-generic with
megaraid_sas, except for the separate passthrough channels that the real
hardware has for things like tape drives.
> However, since Alex Graf is facing similar problems with the AHCI HBA of
> his maybe we could retry again ...
AHCI is a ATA adapter, and should never be used with scsi-generic for
disks. Only for the ATAPI-attached cdroms/tapes/etc it could be used,
although it's quite pointless.
next prev parent reply other threads:[~2010-12-22 13:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-21 3:25 [Qemu-devel] scsi-generic and max request size Benjamin Herrenschmidt
2010-12-21 3:38 ` ronnie sahlberg
2010-12-21 3:52 ` Benjamin Herrenschmidt
2010-12-21 8:44 ` Hannes Reinecke
2010-12-21 22:05 ` Benjamin Herrenschmidt
2010-12-22 13:54 ` Hannes Reinecke
2010-12-22 13:27 ` Christoph Hellwig [this message]
2010-12-22 22:06 ` Benjamin Herrenschmidt
2010-12-22 23:19 ` Alexander Graf
2010-12-22 21:59 ` Benjamin Herrenschmidt
2010-12-22 23:23 ` Alexander Graf
2010-12-22 23:35 ` Benjamin Herrenschmidt
2010-12-22 23:39 ` Alexander Graf
2010-12-22 23:44 ` Benjamin Herrenschmidt
2010-12-22 23:49 ` Alexander Graf
2010-12-23 0:00 ` Benjamin Herrenschmidt
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