On Wed, 2008-07-09 at 10:48 -0600, Bjorn Helgaas wrote: > On Tuesday 08 July 2008 01:04:52 am Zhao Yakui wrote: > > >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. > > This is an obscure detail; can you add a specific spec reference > to your commit log? I think the relevant section is 6.3.7 of > the 3.0b spec. Thanks for pointing this. The detail info is listed in the section 6.3.7 of ACPI 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. And OS should continue enumeration below >a device whose _STA returns this bit combination. I will add this to the commit log. > > > 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 | 16 ++++++++-------- > > drivers/acpi/scan.c | 35 +++++++++++++++++++++++++---------- > > drivers/pnp/pnpacpi/core.c | 6 +++++- > > 3 files changed, 38 insertions(+), 19 deletions(-) > > > > Index: linux-2.6/drivers/acpi/bus.c > > =================================================================== > > --- linux-2.6.orig/drivers/acpi/bus.c > > +++ linux-2.6/drivers/acpi/bus.c > > @@ -95,21 +95,21 @@ 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 | > > 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", > > Index: linux-2.6/drivers/acpi/scan.c > > =================================================================== > > --- linux-2.6.orig/drivers/acpi/scan.c > > +++ linux-2.6/drivers/acpi/scan.c > > @@ -264,6 +264,13 @@ int acpi_match_device_ids(struct acpi_de > > { > > const struct acpi_device_id *id; > > > > + /* > > + * If the device is not present, it is unnecessary to load device > > + * driver for it. > > + */ > > + if (!device->status.present) > > + return -ENODEV; > > + > > if (device->flags.hardware_id) { > > for (id = ids; id->id[0]; id++) { > > if (!strcmp((char*)id->id, device->pnp.hardware_id)) > > @@ -1239,15 +1246,18 @@ acpi_add_single_object(struct acpi_devic > > result = -ENODEV; > > goto end; > > } > > - if (!device->status.present) { > > - /* Bay and dock should be handled even if absent */ > > - if (!ACPI_SUCCESS( > > - acpi_is_child_device(device, acpi_bay_match)) && > > - !ACPI_SUCCESS( > > - acpi_is_child_device(device, acpi_dock_match))) { > > - result = -ENODEV; > > - goto end; > > - } > > + /* > > + * When the device is neither present nor functional, the > > + * device should not be added to Linux ACPI device tree. > > + * When the status of the device is not present but functinal, > > + * it should be added to Linux ACPI tree. For example : bay > > + * device , dock device. > > + * In such conditions it is unncessary to check whether it is > > + * bay device or dock device. > > + */ > > + if (!device->status.present && !device->status.functional) { > > + result = -ENODEV; > > + goto end; > > } > > break; > > default: > > @@ -1420,7 +1430,12 @@ 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/drivers/pnp/pnpacpi/core.c > > =================================================================== > > --- linux-2.6.orig/drivers/pnp/pnpacpi/core.c > > +++ linux-2.6/drivers/pnp/pnpacpi/core.c > > @@ -150,9 +150,13 @@ static int __init pnpacpi_add_device(str > > 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)); > > > > > > -- > > 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 > > > > -- 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
