1 files changed, 43 insertions, 10 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 0dc44945725e..e6311f432edf 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -48,6 +48,23 @@ EXPORT_SYMBOL(acpi_root_dir);
 
 #define STRUCT_TO_INT(s)        (*((int*)&s))
 
+static int set_power_nocheck(const struct dmi_system_id *id)
+{
+        printk(KERN_NOTICE PREFIX "%s detected - "
+                "disable power check in power transistion\n", id->ident);
+        acpi_power_nocheck = 1;
+        return 0;
+}
+static struct dmi_system_id __cpuinitdata power_nocheck_dmi_table[] = {
+        {
+        set_power_nocheck, "HP Pavilion 05", {
+        DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
+        DMI_MATCH(DMI_SYS_VENDOR, "HP Pavilion 05"),
+        DMI_MATCH(DMI_PRODUCT_VERSION, "2001211RE101GLEND") }, NULL},
+        {},
+};
+
+
 /* --------------------------------------------------------------------------
                                 Device Management
    -------------------------------------------------------------------------- */
@@ -95,21 +112,21 @@ int acpi_bus_get_status(struct acpi_device *device)
         }
 
         /*
-         * Otherwise we assume the status of our parent (unless we don't
-         * have one, in which case status is implied).
+         * According to ACPI spec some device can be present and functional
+         * even if the parent is not present but functional.
+         * In such conditions the child device should not inherit the status
+         * from the parent.
          */
-        else if (device->parent)
-                device->status = device->parent->status;
         else
                 STRUCT_TO_INT(device->status) =
                     ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
                     ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;
 
         if (device->status.functional && !device->status.present) {
-                printk(KERN_WARNING PREFIX "Device [%s] status [%08x]: "
-                       "functional but not present; setting present\n",
-                       device->pnp.bus_id, (u32) STRUCT_TO_INT(device->status));
-                device->status.present = 1;
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]: "
+                       "functional but not present;\n",
+                        device->pnp.bus_id,
+                        (u32) STRUCT_TO_INT(device->status)));
         }
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] status [%08x]\n",
@@ -223,7 +240,19 @@ int acpi_bus_set_power(acpi_handle handle, int state)
         /*
          * Get device's current power state
          */
-        acpi_bus_get_power(device->handle, &device->power.state);
+        if (!acpi_power_nocheck) {
+                /*
+                 * Maybe the incorrect power state is returned on the bogus
+                 * bios, which is different with the real power state.
+                 * For example: the bios returns D0 state and the real power
+                 * state is D3. OS expects to set the device to D0 state. In
+                 * such case if OS uses the power state returned by the BIOS,
+                 * the device can't be transisted to the correct power state.
+                 * So if the acpi_power_nocheck is set, it is unnecessary to
+                 * get the power state by calling acpi_bus_get_power.
+                 */
+                acpi_bus_get_power(device->handle, &device->power.state);
+        }
         if ((state == device->power.state) && !device->flags.force_power_state) {
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n",
                                   state));
@@ -833,7 +862,11 @@ static int __init acpi_init(void)
                 }
         } else
                 disable_acpi();
-
+        /*
+         * If the laptop falls into the DMI check table, the power state check
+         * will be disabled in the course of device power transistion.
+         */
+        dmi_check_system(power_nocheck_dmi_table);
         return result;
 }