Subject: ACPI : Load device driver according to the status of acpi device >From : Zhao Yakui <yakui.zhao@xxxxxxxxx> 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. http://bugzilla.kernel.org/show_bug.cgi?id=3358 Signed-off-by: Zhao Yakui <yakui.zhao@xxxxxxxxx> Signed-off-by: Li Shaohua <shaohua.li@xxxxxxxxx> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx> --- drivers/acpi/bus.c | 11 +++++------ drivers/acpi/scan.c | 20 ++++++++++++++++++-- drivers/pnp/pnpacpi/core.c | 6 +++++- 3 files changed, 28 insertions(+), 9 deletions(-) Index: linux-2.6.24-rc4/drivers/acpi/bus.c =================================================================== --- linux-2.6.24-rc4.orig/drivers/acpi/bus.c +++ linux-2.6.24-rc4/drivers/acpi/bus.c @@ -97,11 +97,11 @@ int acpi_bus_get_status(struct acpi_devi } /* - * 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 | @@ -109,9 +109,8 @@ int acpi_bus_get_status(struct acpi_devi if (device->status.functional && !device->status.present) { printk(KERN_WARNING PREFIX "Device [%s] status [%08x]: " - "functional but not present; setting present\n", + "functional but not 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]\n", Index: linux-2.6.24-rc4/drivers/acpi/scan.c =================================================================== --- linux-2.6.24-rc4.orig/drivers/acpi/scan.c +++ linux-2.6.24-rc4/drivers/acpi/scan.c @@ -257,6 +257,11 @@ int acpi_match_device_ids(struct acpi_de const struct acpi_device_id *ids) { const struct acpi_device_id *id; + /* + * If the device is not present, the device driver is not loaded. + */ + if (!device->status.present) + return -ENODEV; if (device->flags.hardware_id) { for (id = ids; id->id[0]; id++) { @@ -1131,7 +1136,13 @@ acpi_add_single_object(struct acpi_devic case ACPI_BUS_TYPE_PROCESSOR: case ACPI_BUS_TYPE_DEVICE: result = acpi_bus_get_status(device); - if (ACPI_FAILURE(result) || !device->status.present) { + if (ACPI_FAILURE(result) || (!device->status.present && + !device->status.functional)) { + /* + * When the device is neither present nor functional, the + * device should not be added to Linux ACPI device tree. + */ + result = -ENOENT; goto end; } @@ -1306,7 +1317,12 @@ static int acpi_bus_scan(struct acpi_dev * TBD: Need notifications and other detection mechanisms * in place before we can fully implement this. */ - if (child->status.present) { + /* + * When the device is not present but functional, it is also + * necessary to scan the children of this device. + */ + if ((child->status.present) || (!child->status.present && + child->status.functional)) { status = acpi_get_next_object(ACPI_TYPE_ANY, chandle, NULL, NULL); if (ACPI_SUCCESS(status)) { Index: linux-2.6.24-rc4/drivers/pnp/pnpacpi/core.c =================================================================== --- linux-2.6.24-rc4.orig/drivers/pnp/pnpacpi/core.c +++ linux-2.6.24-rc4/drivers/pnp/pnpacpi/core.c @@ -166,9 +166,13 @@ static int __init pnpacpi_add_device(str struct pnp_id *dev_id; 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 = kzalloc(sizeof(struct pnp_dev), GFP_KERNEL); - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
