ACPI: ibm-acpi: allow module to load when acpi notifiers can't be set (v2)

This patch allows for ibm-acpi to coexist (with diminished functionality) with
other drivers like ACPI_BAY.  ibm-acpi will simply disable the functions it is
not able to register ACPI notifiers for.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Chris Wedgwood <cw@f00f.org>
Cc: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index 36901362fd24..dc1096608f43 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -2507,7 +2507,7 @@ static int __init setup_notify(struct ibm_struct *ibm)
         ret = acpi_bus_get_device(*ibm->handle, &ibm->device);
         if (ret < 0) {
                 printk(IBM_ERR "%s device not present\n", ibm->name);
-                return 0;
+                return -ENODEV;
         }
 
         acpi_driver_data(ibm->device) = ibm;
@@ -2516,8 +2516,13 @@ static int __init setup_notify(struct ibm_struct *ibm)
         status = acpi_install_notify_handler(*ibm->handle, ibm->type,
                                              dispatch_notify, ibm);
         if (ACPI_FAILURE(status)) {
-                printk(IBM_ERR "acpi_install_notify_handler(%s) failed: %d\n",
-                       ibm->name, status);
+                if (status == AE_ALREADY_EXISTS) {
+                        printk(IBM_NOTICE "another device driver is already handling %s events\n",
+                                ibm->name);
+                } else {
+                        printk(IBM_ERR "acpi_install_notify_handler(%s) failed: %d\n",
+                                ibm->name, status);
+                }
                 return -ENODEV;
         }
         ibm->notify_installed = 1;
@@ -2553,6 +2558,8 @@ static int __init register_driver(struct ibm_struct *ibm)
         return ret;
 }
 
+static void ibm_exit(struct ibm_struct *ibm);
+
 static int __init ibm_init(struct ibm_struct *ibm)
 {
         int ret;
@@ -2594,6 +2601,12 @@ static int __init ibm_init(struct ibm_struct *ibm)
 
         if (ibm->notify) {
                 ret = setup_notify(ibm);
+                if (ret == -ENODEV) {
+                        printk(IBM_NOTICE "disabling subdriver %s\n",
+                                ibm->name);
+                        ibm_exit(ibm);
+                        return 0;
+                }
                 if (ret < 0)
                         return ret;
         }