Re: [Qemu-devel] Do you have a use for a tester of virtio-scsi with CD drives ?

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Paolo Bonzini wrote:
> It would be more interesting if you tried again the failure cases with a
> virtio drive (if=virtio).  It would appear as /dev/vda but you can issue
> SG_IO to it.  This would isolate the failure to the kernels vs. the SCSI
> subsystem.

Will do. I am currently fighting with eSATA and may have to give up
the planned Blu-ray tests, after USB already failed so dramatically.

The external drive does not work properly with 3.0 Gbps.
This is a known shortcomming of my test machine's eSATA cabling or of
the eSATA box (i only have one of either kind, so i cannot cross-check).

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Interesting insight:

The failure at 3.0 Gbps throws on the host the same sense code as
FORMAT UNIT does on the guest with the internal SATA drive, which
runs at 1.5 Gbps by miracle.
  Sense Key B "Command aborted", ASC 00 ASCQ 00

So the sense code with FORMAT UNIT might stem from the host kernel
and not from qemu.

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Other than Debian 5 the newer Debian 6 kernel 2.6.32-5-amd64 does not
reset to 1.5 Gps after the first transport failure.
  Nov  6 10:59:55 debian2 kernel: [ 2025.849176] ata5: hard resetting link
  Nov  6 10:59:56 debian2 kernel: [ 2026.780105] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
I dimly remember that i'd need to patch initrd to get the kernel
module option into effect at an early boot stage.
I haven't done this since two years and this could possibly change the
whole test setup.

Better would be to know, why the internal SATA drive is started with
1.5 Gbps at boot time
  Nov  6 10:26:15 debian2 kernel: [    1.241546] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
  Nov  6 10:26:15 debian2 kernel: [    1.242406] ata3.00: ATAPI: TSSTcorp CDDVDW SH-S223B, SB02, max UDMA/100

In contrast to the eSATA attached drive
  Nov  6 10:26:15 debian2 kernel: [    1.688050] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
  Nov  6 10:26:15 debian2 kernel: [    1.693623] ata5.00: ATAPI: Optiarc BD RW BD-5300S, 1.04, max UDMA/100

On Debian 5, the internal drive was run with 3.0 Gbps and worked fine.

Miracles of system administration ...

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Have a nice day :)

Thomas