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>

1 files changed, 1 insertions, 19 deletions

diff --git a/drivers/mfd/lpc_ich.c b/drivers/mfd/lpc_ich.c
index 027cc8f86132..a05fdfc2ebcf 100644
--- 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;
 }