Hi Wolfram, Mika,
On Fri, 24 Aug 2018 15:08:01 +0200, Wolfram Sang wrote:
> On Thu, Aug 23, 2018 at 11:45:53AM +0300, Mika Westerberg wrote:
> > Commit 7ae81952cda ("i2c: i801: Allow ACPI SystemIO OpRegion to conflict
> > with PCI BAR") made it possible for AML code to access SMBus I/O ports
> > by installing custom SystemIO OpRegion handler and blocking i80i driver
> > access upon first AML read/write to this OpRegion.
> >
> > However, while ThinkPad T560 does have SystemIO OpRegion declared under
> > the SMBus device, it does not access any of the SMBus registers:
> >
> > Device (SMBU)
> > {
> > ...
> >
> > OperationRegion (SMBP, PCI_Config, 0x50, 0x04)
> > Field (SMBP, DWordAcc, NoLock, Preserve)
> > {
> > , 5,
> > TCOB, 11,
> > Offset (0x04)
> > }
> >
> > Name (TCBV, 0x00)
> > Method (TCBS, 0, NotSerialized)
> > {
> > If ((TCBV == 0x00))
> > {
> > TCBV = (\_SB.PCI0.SMBU.TCOB << 0x05)
> > }
> >
> > Return (TCBV) /* \_SB_.PCI0.SMBU.TCBV */
> > }
> >
> > OperationRegion (TCBA, SystemIO, TCBS (), 0x10)
> > Field (TCBA, ByteAcc, NoLock, Preserve)
> > {
> > Offset (0x04),
> > , 9,
> > CPSC, 1
> > }
> > }
> >
> > Problem with the current approach is that it blocks all I/O port access
> > and because this system has touchpad connected to the SMBus controller
> > after first AML access (happens during suspend/resume cycle) the
> > touchpad fails to work anymore.
> >
> > Fix this so that we allow ACPI AML I/O port access if it does not touch
> > the region reserved for the SMBus.
> >
> > Fixes: 7ae81952cda ("i2c: i801: Allow ACPI SystemIO OpRegion to conflict with PCI BAR")
> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=200737
> > Reported-by: Yussuf Khalil <dev@xxxxxxxxxx>
> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
>
> I'll give Jean a few more days to comment but will apply it for -rc2
> latest.
Sorry for the late answer, I'm back from vacation.
On the principle, the change looks sane to me. However I suspect
there's an off-by-one bug:
> +{
> + return address >= priv->smba &&
> + address < pci_resource_end(priv->pci_dev, SMBBAR);
> +}
Shouldn't the second test use "<=" instead of "<"?
Other than that, looks good to me, so you can add my:
Reviewed-by: Jean Delvare <jdelvare@xxxxxxx>
Thanks,
--
Jean Delvare
SUSE L3 Support
