From mboxrd@z Thu Jan  1 00:00:00 1970
From: Robert Hancock <hancockrwd@gmail.com>
Subject: Re: Suggestions for debugging ata_piix and ahci driver failures on
 Xen pv_ops dom0 kernel (2.6.29-rcX)
Date: Thu, 05 Feb 2009 18:45:02 -0600
Message-ID: <498B880E.6070001@gmail.com>
References: <20090205082843.GD15052@edu.joroinen.fi>
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To: =?ISO-8859-1?Q?Pasi_K=E4rkk=E4inen?= <pasik@iki.fi>
Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org

Pasi K=E4rkk=E4inen wrote:
> Hello!
>=20
> I'm trying to figure out what's wrong with the pv_ops dom0 kernel/pat=
ches [1]
> causing at least ata_piix and ahci drivers to fail to work.
>=20
> There was legacy IRQ enabling problem earlier with the pv_ops dom0 pa=
tches,=20
> which pretty much prevented the disks from being detected.. but that =
got fixed.=20
> It could still be something related to Xen/dom0 irq handling..=20
>=20
> I'd be glad if someone could take a look at this 2.6.29-rc3-tip pv_op=
s dom0 kernel boot log
> and comment about _possible_ causes for such behaviour of ata_piix an=
d ahci:
>=20
> http://pasik.reaktio.net/xen/pv_ops-dom0-debug/pv_ops-dom0-bootlog-11=
-xen331-linux-2.6.29-rc3-atadebug3.txt
>=20
> In that testing box I have just one IDE hdd attached to ata_piix cont=
roller, the AHCI controller doesn't
> have any disks attached.
>=20
> The exact same kernel works OK without problems on baremetal without =
Xen
> hypervisor.=20

Seems like me like ata_piix is not receiving any interrupts.. the=20
polling-based IDENTIFY and SET FEATURES work, but the READ NATIVE MAX=20
ADDRESS times out and so does the READ DMA that gets tried next.

Note that the ata_piix controller is in legacy mode, not native mode, s=
o=20
it's using IRQ 14 and 15, not whatever the hardware may otherwise=20
indicate. Could be the problem is related to that.