ATAPI Driver problems

ATAPI Driver problems

[Clemens Helfmeier]

Hi everybody,

I am trying to access the qemu cdrom drive (atapi) with grub2. Unfortunately, 
qemu crashes with "triple faults". A bit of google revealed that this would also 
reboot a real machine, so qemu has reasons for it.

This always happens at the same location of code (0xb3a0 in my case) but the 
output bofore the crash is not always the same. I don't know if output is 
delayed either in qemu or in grub, does anyone know that?

I also wonder why the qemu cdrom drive is not detected as removable nor as cdrom 
drive:

grub> ls (ata2)/
../disk/ata.c:798: opened device ata0 successfully.
../disk/ata.c:803: using block size 0x200 for device ata0.
../disk/ata.c:816: closed device ata0,1.
../disk/ata.c:920: opening ATAPI dev `ata2'
../disk/scsi.c:261: dev opened
../disk/scsi.c:270: inquiry: devtype=0x00 removable=0
qemu: fatal: triple fault

How can i debug the running grub2 in the qemu machine? Is there an easy way with 
gdb? Did someone already get the ATAPI code working somehow? Where can i find 
information on how to access atapi/ata drives?

(the snipped above has been created with my sector size patched svn version)

Any ideas, commens, ...?


 Clemens

Re: ATAPI Driver problems

[Robert Millan]

On Thu, Oct 09, 2008 at 12:23:25PM +0200, Clemens Helfmeier wrote:
> Hi everybody,
> 
> I am trying to access the qemu cdrom drive (atapi) with grub2. Unfortunately, 
> qemu crashes with "triple faults". A bit of google revealed that this would also 
> reboot a real machine, so qemu has reasons for it.
> 
> This always happens at the same location of code (0xb3a0 in my case) but the 
> output bofore the crash is not always the same. I don't know if output is 
> delayed either in qemu or in grub, does anyone know that?
> 
> I also wonder why the qemu cdrom drive is not detected as removable nor as cdrom 
> drive:
> 
> grub> ls (ata2)/
> ../disk/ata.c:798: opened device ata0 successfully.
> ../disk/ata.c:803: using block size 0x200 for device ata0.
> ../disk/ata.c:816: closed device ata0,1.
> ../disk/ata.c:920: opening ATAPI dev `ata2'
> ../disk/scsi.c:261: dev opened
> ../disk/scsi.c:270: inquiry: devtype=0x00 removable=0
> qemu: fatal: triple fault

This code is known to work on qemu AFAIK.  Is that pristine SVN, or your patched
version?

> How can i debug the running grub2 in the qemu machine? Is there an easy way with 
> gdb? Did someone already get the ATAPI code working somehow? Where can i find 
> information on how to access atapi/ata drives?

The wiki has some info on that IIRC

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."