mfd: lpc_ich: Fix a 3.5 kernel regression for iTCO_wdt driver

There are many reports (including 2 of my machines) that iTCO_wdt watchdog
driver fails to be initialized in 3.5 kernel with error message like:

[    5.265175] ACPI Warning: 0x00001060-0x0000107f SystemIO conflicts with Region \_SB_.PCI0.LPCB.TCOI 1 (20120320/utaddress-251)
[    5.265192] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver
[    5.265206] lpc_ich: Resource conflict(s) found affecting iTCO_wdt

The root cause the iTCO_wdt driver in 3.4 probes the HW IO resource from
LPC's PCI config space, while in 3.5 kernel it relies on lpc_ich driver
for the probe, which adds a new acpi_check_resource_conflict() check, and
give up the probe if there is any conflict with ACPI.

Fix it by removing all the checks for iTCO_wdt to keep the same behavior as
3.4 kernel.
https://bugzilla.kernel.org/show_bug.cgi?id=44991

Actually the same check could be removed for the gpio-ich in lpc_ich.c,
but I'm not sure if it will cause problems.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Aaron Sierra <asierra@xes-inc.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Len Brown <len.brown@intel.com>
Cc: Bob Moore <robert.moore@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/drivers/mfd/lpc_ich.c b/drivers/mfd/lpc_ich.c
index 027cc8f..a05fdfc 100644 (file)
--- a/drivers/mfd/lpc_ich.c
+++ b/drivers/mfd/lpc_ich.c
@@ -765,7 +765,6 @@ static int __devinit lpc_ich_init_wdt(struct pci_dev *dev,
        u32 base_addr_cfg;
        u32 base_addr;
        int ret;
-       bool acpi_conflict = false;
        struct resource *res;
 
        /* Setup power management base register */
@@ -780,20 +779,11 @@ static int __devinit lpc_ich_init_wdt(struct pci_dev *dev,
        res = wdt_io_res(ICH_RES_IO_TCO);
        res->start = base_addr + ACPIBASE_TCO_OFF;
        res->end = base_addr + ACPIBASE_TCO_END;
-       ret = acpi_check_resource_conflict(res);
-       if (ret) {
-               acpi_conflict = true;
-               goto wdt_done;
-       }
 
        res = wdt_io_res(ICH_RES_IO_SMI);
        res->start = base_addr + ACPIBASE_SMI_OFF;
        res->end = base_addr + ACPIBASE_SMI_END;
-       ret = acpi_check_resource_conflict(res);
-       if (ret) {
-               acpi_conflict = true;
-               goto wdt_done;
-       }
+
        lpc_ich_enable_acpi_space(dev);
 
        /*
@@ -813,11 +803,6 @@ static int __devinit lpc_ich_init_wdt(struct pci_dev *dev,
                res = wdt_mem_res(ICH_RES_MEM_GCS);
                res->start = base_addr + ACPIBASE_GCS_OFF;
                res->end = base_addr + ACPIBASE_GCS_END;
-               ret = acpi_check_resource_conflict(res);
-               if (ret) {
-                       acpi_conflict = true;
-                       goto wdt_done;
-               }
        }
 
        lpc_ich_finalize_cell(&lpc_ich_cells[LPC_WDT], id);
@@ -825,9 +810,6 @@ static int __devinit lpc_ich_init_wdt(struct pci_dev *dev,
                                1, NULL, 0);
 
 wdt_done:
-       if (acpi_conflict)
-               pr_warn("Resource conflict(s) found affecting %s\n",
-                               lpc_ich_cells[LPC_WDT].name);
        return ret;
 }