SCSI bus failures with qemu-arm in kernel 3.8+

On 13-08-11 08:40 PM, Guenter Roeck wrote:

On 08/11/2013 03:04 PM, Russell King - ARM Linux wrote:

quoted

On Sun, Aug 11, 2013 at 08:54:43AM -0700, Guenter Roeck wrote:

quoted

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.

Maybe Paul can comment, as he wrote the patch.

If I recall correctly, I'd showed the patch to Russell at the time (via
IRC, I believe) and he'd told me essentially the same thing as the above
paragraph, which is why I didn't put it in the patch system, and why the
commit log of the yocto patch (http://goo.gl/riEZXY) reads as it does
(i.e. it is unclear what the real swizzle is).  If docs appear that help
clarify where the real issue is, then great.

Paul.
--

If it helps, I tried with qemu 1.4.0 from Ubuntu 13.4, qemu 1.4.0 from Poky 1.4.0-1,
and qemu 1.5.2 from the qemu repository.

Copying qemu-devel to increase the audience.

Guenter