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Re: [Qemu-devel] Small issue in the IDE emulation
From: |
Vincent Sanders |
Subject: |
Re: [Qemu-devel] Small issue in the IDE emulation |
Date: |
Sat, 4 Oct 2008 12:51:00 +0100 |
User-agent: |
Mutt/1.5.17+20080114 (2008-01-14) |
On Sat, Oct 04, 2008 at 01:30:37PM +0200, Samuel Thibault wrote:
> Vincent Sanders, le Sat 04 Oct 2008 12:10:02 +0100, a écrit :
> > While doing some other work I have come across a small issue with the
> > DIAGNOSE command in the qemu IDE implementation. The status register
> > value is dependant on the drive being a packet device or not. The
> > simple patch (attached) fixes this.
> >
> > === modified file 'hw/ide.c'
> > --- hw/ide.c 2008-10-01 01:43:16 +0000
> > +++ hw/ide.c 2008-10-04 10:56:58 +0000
> > @@ -2308,8 +2308,15 @@
> > break;
> > case WIN_DIAGNOSE:
> > ide_set_signature(s);
> > - s->status = READY_STAT | SEEK_STAT;
> > - s->error = 0x01;
> > + if (s->is_cdrom)
> > + s->status = 0; /* ATAPI spec (v6) section 9.10 defines
> > packet
> > + * devices to return a clear status register
> > + * with READY_STAT *not* set. */
>
> But shouldn't we at least set SEEK_STAT?
Spec says:
"If the device implements the PACKET command feature set, the device
SHALL clear bits 6,5,4,3,2 and 0 in the Status register to zero."
I beleive a version of this spec is available online
http://www.t10.org/t13/project/d1410r3a-ATA-ATAPI-6.pdf page 362 (pdf
page is 376 there is an offset) is where this is mentioned.
And I just went and checked a couple of physical devices doing it and
they do indeed behave as per the spec.
A few boot loaders that support older drive diagnostics through this
method seem to get a bit confused if the status is not clear.
>
> Samuel
>
>
--
Regards Vincent
http://www.kyllikki.org/
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