On Mon, Feb 24, 2020 at 12:51:25PM +0200, Mika Westerberg wrote:
> > I'm wondering if
> >
> > pci_dev_is_present(...);
> >
> > returns false here.
>
> Well that might also be the case since lspci shows this:
>
> 00:1f.0 ISA bridge: Intel Corporation Z390 Chipset LPC/eSPI Controller (rev 10)
> 00:1f.3 Audio device: Intel Corporation Cannon Lake PCH cAVS (rev 10)
> 00:1f.4 SMBus: Intel Corporation Cannon Lake PCH SMBus Controller (rev 10)
>
> PMC is 1f.2 and not present here. However, it may be that the PMC is
> still there it just does not "enumerate" because its devid/vendorid are
> set to 0xffff. Similar hiding was done for the P2SB bridge.
Actually I think this is the case here.
I don't know the iTCO_wdt well enough to say if it could live without
the ICH_RES_IO_SMI. It looks like this register is used to disable SMI
generation but not sure how well it works if it is left to BIOS to
configure. I suppose these systems should use WDAT instead.
Martin, can you try the below patch?
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index ba87305f4332..c16e5ad08641 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1593,7 +1593,7 @@ i801_add_tco_cnl(struct i801_priv *priv, struct pci_dev *pci_dev,
static void i801_add_tco(struct i801_priv *priv)
{
u32 base_addr, tco_base, tco_ctl, ctrl_val;
- struct pci_dev *pci_dev = priv->pci_dev;
+ struct pci_dev *pmc_dev, *pci_dev = priv->pci_dev;
struct resource tco_res[3], *res;
unsigned int devfn;
@@ -1620,7 +1620,12 @@ static void i801_add_tco(struct i801_priv *priv)
* Power Management registers.
*/
devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 2);
- pci_bus_read_config_dword(pci_dev->bus, devfn, ACPIBASE, &base_addr);
+ pmc_dev = pci_get_slot(pci_dev->bus, devfn);
+ if (!pmc_dev) {
+ dev_info(&pci_dev->dev, "PMC device disabled, not enabling iTCO\n");
+ return;
+ }
+ pci_read_config_dword(pmc_dev, ACPIBASE, &base_addr);
res = &tco_res[ICH_RES_IO_SMI];
res->start = (base_addr & ~1) + ACPIBASE_SMI_OFF;
@@ -1630,15 +1635,17 @@ static void i801_add_tco(struct i801_priv *priv)
/*
* Enable the ACPI I/O space.
*/
- pci_bus_read_config_dword(pci_dev->bus, devfn, ACPICTRL, &ctrl_val);
+ pci_read_config_dword(pmc_dev, ACPICTRL, &ctrl_val);
ctrl_val |= ACPICTRL_EN;
- pci_bus_write_config_dword(pci_dev->bus, devfn, ACPICTRL, ctrl_val);
+ pci_write_config_dword(pmc_dev, ACPICTRL, ctrl_val);
if (priv->features & FEATURE_TCO_CNL)
priv->tco_pdev = i801_add_tco_cnl(priv, pci_dev, tco_res);
else
priv->tco_pdev = i801_add_tco_spt(priv, pci_dev, tco_res);
+ pci_dev_put(pmc_dev);
+
if (IS_ERR(priv->tco_pdev))
dev_warn(&pci_dev->dev, "failed to create iTCO device\n");
}
