Luca Tettamanti wrote:
On Mon, Oct 19, 2009 at 2:14 PM, Tomasz Chmielewski <mangoo@xxxxxxxx> wrote:
lspci implies that the virtio block device is a "SCSI storage controller",
i.e.:
00:05.0 SCSI storage controller: Qumranet, Inc. Virtio block device
However, virtio block devide does not have much to do with SCSI (in sense:
sdparm does not think it is a SCSI device; virtio_blk does not depend on any
SCSI moduled like sd_mod).
Is "SCSI storage controller" a proper description for this device?
It does not talk SCSI protocol if that's what you're asking. The
description you see comes from the PCI class (storage controller) and
subclass (SCSI controller); the meaning of the class/subclass is fixed
by the PCI standard.
So why was "SCSI storage controller" any better than "IDE interface" or
"SATA controller" for virtio block device, if it does not talk SCSI
protocol (other than "SCSI storage controller" being the first on the
list of subclasses)?
Doesn't "80 Mass storage controller" ("0x80 0x00 Other mass storage
controller") fit better for virtio block device?
Generally, I see that 0x80 is reserved for "other/unspecified" types of
devices from a given PCI class.
Let me know if I'm asking a stupid question ;)
C 01 Mass storage controller
00 SCSI storage controller
01 IDE interface
02 Floppy disk controller
03 IPI bus controller
04 RAID bus controller
05 ATA controller
20 ADMA single stepping
30 ADMA continuous operation
06 SATA controller
00 Vendor specific
01 AHCI 1.0
07 Serial Attached SCSI controller
80 Mass storage controller
--
Tomasz Chmielewski
http://wpkg.org
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