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authorZhao Yakui <yakui.zhao@intel.com>2008-08-11 13:40:22 +0800
committerLen Brown <len.brown@intel.com>2008-10-22 18:00:50 -0400
commit39a0ad871000d2a016a4fa113a6e53d22aabf25d (patch)
treee4ff7eabccc74b2d16e80d78c2e255d2d004cd4d /drivers/pnp/pnpacpi
parent6415e12ba0f92a54f02d9c4ecaa3c82f35f3d335 (diff)
downloadlinux-linaro-stable-39a0ad871000d2a016a4fa113a6e53d22aabf25d.tar.gz
ACPI : Load device driver according to the status of acpi device
According to ACPI spec when the status of some device is not present but functional, the device is valid and the children of this device should be enumerated. It means that the device should be added to linux acpi device tree. But the device driver for this device should not be loaded. The detailed info can be found in the section 6.3.7 of ACPI 3.0b spec. _STA may return bit 0 clear (not present) with bit 3 set (device is functional). This case is used to indicate a valid device for which no device driver should be loaded (for example, a bridge device.). Children of this device may be present and valid. OS should continue enumeration below a device whose _STA returns this bit combination http://bugzilla.kernel.org/show_bug.cgi?id=3358 Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> Signed-off-by: Li Shaohua <shaohua.li@intel.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/pnp/pnpacpi')
-rw-r--r--drivers/pnp/pnpacpi/core.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
index c1b9ea34977b..98b9df7776e9 100644
--- a/drivers/pnp/pnpacpi/core.c
+++ b/drivers/pnp/pnpacpi/core.c
@@ -148,9 +148,13 @@ static int __init pnpacpi_add_device(struct acpi_device *device)
acpi_status status;
struct pnp_dev *dev;
+ /*
+ * If a PnPacpi device is not present , the device
+ * driver should not be loaded.
+ */
status = acpi_get_handle(device->handle, "_CRS", &temp);
if (ACPI_FAILURE(status) || !ispnpidacpi(acpi_device_hid(device)) ||
- is_exclusive_device(device))
+ is_exclusive_device(device) || (!device->status.present))
return 0;
dev = pnp_alloc_dev(&pnpacpi_protocol, num, acpi_device_hid(device));