SCSI bus failures with qemu-arm in kernel 3.8+

[Russell King - ARM Linux]

On Sun, Aug 11, 2013 at 08:54:43AM -0700, Guenter Roeck wrote:
> Hi,
>
> trying to boot arm versatile images with qemu results in the following error
> if I try to boot with a disk image.
>
>      sym0: <895a> rev 0x0 at pci 0000:00:0d.0 irq 92
>      sym0: SCSI BUS has been reset.
>      scsi0 : sym-2.2.3
>      [...]
>      scsi 0:0:0:0: ABORT operation started
>      scsi 0:0:0:0: ABORT operation timed-out.
>      [...]
>
> Yocto's 3.8 kernel images work, upstream kernels 3.8 and later fail
> (I did not check if/how earlier kernels are affected).
>
> Tracking this down shows that the problem is known and has been fixed with
> commit 351d1339 (arm: add dummy swizzle for versatile with qemu) in the
> Yocto 3.8 kernel at git://git.yoctoproject.org/linux-yocto-3.8.
>
> Would it be possible to submit this patch for inclusion into affected upstream kernels ?

It could be that it's qemu's PCI routing is wrong - it's not the first
time that qemu has got something wrong.

Unfortunately, the PCI routing is totally undocumented, and as I understand
it, there's very few backplanes out there now that finding out their real
routing is virtually impossible.  I'm loathed to change it unless someone
can point to a definitive source of information on this.