ACPI: EC: Enable boot EC before bus_scan

Some _STA methods called during bus_scan() might require EC region handler,
which might be enabled later in the scan.
Enable it explicitly before scan to avoid errors.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=9627

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 19 insertions, 1 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index d411017f8c06..97dc16155a55 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -892,6 +892,17 @@ static int acpi_ec_stop(struct acpi_device *device, int type)
         return 0;
 }
 
+int __init acpi_boot_ec_enable(void)
+{
+        if (!boot_ec || boot_ec->handlers_installed)
+                return 0;
+        if (!ec_install_handlers(boot_ec)) {
+                first_ec = boot_ec;
+                return 0;
+        }
+        return -EFAULT;
+}
+
 int __init acpi_ec_ecdt_probe(void)
 {
         int ret;
@@ -924,9 +935,10 @@ int __init acpi_ec_ecdt_probe(void)
                         goto error;
                 /* We really need to limit this workaround, the only ASUS,
                  * which needs it, has fake EC._INI method, so use it as flag.
+                 * Keep boot_ec struct as it will be needed soon.
                  */
                 if (ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI", &x)))
-                        goto error;
+                        return -ENODEV;
         }
 
         ret = ec_install_handlers(boot_ec);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 5b4d462117cf..cbfe9ae7a9e5 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1449,6 +1449,8 @@ static int acpi_bus_scan_fixed(struct acpi_device *root)
         return result;
 }
 
+int __init acpi_boot_ec_enable(void);
+
 static int __init acpi_scan_init(void)
 {
         int result;
@@ -1480,6 +1482,10 @@ static int __init acpi_scan_init(void)
          * Enumerate devices in the ACPI namespace.
          */
         result = acpi_bus_scan_fixed(acpi_root);
+
+        /* EC region might be needed at bus_scan, so enable it now */
+        acpi_boot_ec_enable();
+
         if (!result)
                 result = acpi_bus_scan(acpi_root, &ops);