On Monday, November 11, 2013 07:03:18 AM Greg Kroah-Hartman wrote: > On Mon, Nov 11, 2013 at 02:45:39PM +0100, Rafael J. Wysocki wrote: > > On Monday, November 11, 2013 09:21:40 AM Lan Tianyu wrote: > > > On 2013年11月10日 08:58, Rafael J. Wysocki wrote: > > > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > > > > > Modify struct acpi_dev_node to contain a pointer to struct device > > > > ambedded in the struct acpi_device associated with the given device > > > > object (that is, its ACPI companion device) instead of an ACPI handle > > > > corresponding to that struct acpi_device. Introduce two new macros > > > > for manipulating that pointer in a CONFIG_ACPI-safe way, > > > > ACPI_COMPANION() and ACPI_COMPANION_SET(), and rework the > > > > ACPI_HANDLE() macro to take the above changes into account. > > > > Drop the ACPI_HANDLE_SET() macro entirely and rework its users to > > > > use ACPI_COMPANION_SET() instead. For some of them who used to > > > > pass the result of acpi_get_child() directly to ACPI_HANDLE_SET() > > > > introduce a helper routine acpi_preset_companion() doing an > > > > equivalent thing. > > > > > > > > The rationale for using a struct device pointer instead of a > > > > struct acpi_device one as the member of struct acpi_dev_node is > > > > that it allows device.h to avoid including linux/acpi.h which would > > > > introduce quite a bit of compilation overhead for stuff that doesn't > > > > care about ACPI. > > > > In turn, moving the macros to linux/acpi.h forces > > > > the stuff that does care about ACPI to include that file as > > > > appropriate anyway. > > > > > > How about declaring "struct acpi_device" in the device.h? This can help > > > to use struct acpi_device without including linux/acpi.h. > > > > > > struct iommu_ops and struct iommu_group have been used by the same way > > > in the device.h. > > > > Yes, they are. Well, that appears to work too. > > > > Updated patch is appended. It also contains some fixes for problems reported > > by the auto build system and it's been tested on x86-64 now, so it should be > > reasonably close to final. > > > > Thanks, > > Rafael > > > > > > --- > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Subject: ACPI / driver core: Store an ACPI device pointer in struct acpi_dev_node > > > > Modify struct acpi_dev_node to contain a pointer to struct acpi_device > > associated with the given device object (that is, its ACPI companion > > device) instead of an ACPI handle corresponding to it. Introduce two > > new macros for manipulating that pointer in a CONFIG_ACPI-safe way, > > ACPI_COMPANION() and ACPI_COMPANION_SET(), and rework the > > ACPI_HANDLE() macro to take the above changes into account. > > Drop the ACPI_HANDLE_SET() macro entirely and rework its users to > > use ACPI_COMPANION_SET() instead. For some of them who used to > > pass the result of acpi_get_child() directly to ACPI_HANDLE_SET() > > introduce a helper routine acpi_preset_companion() doing an > > equivalent thing. > > > > The main motivation for doing this is that there are things > > represented by struct acpi_device objects that don't have valid > > ACPI handles (so called fixed ACPI hardware features, such as > > power and sleep buttons) and we would like to create platform > > device objects for them and "glue" them to their ACPI companions > > in the usual way (which currently is impossible due to the > > lack of valid ACPI handles). However, there are more reasons > > why it may be useful. > > > > First, struct acpi_device pointers allow of much better type checking > > than void pointers which are ACPI handles, so it should be more > > difficult to write buggy code using modified struct acpi_dev_node > > and the new macros. Second, the change should help to reduce (over > > time) the number of places in which the result of ACPI_HANDLE() is > > passed to acpi_bus_get_device() in order to obtain a pointer to the > > struct acpi_device associated with the given "physical" device, > > because now that pointer is returned by ACPI_COMPANION() directly. > > Finally, the change should make it easier to write generic code that > > will build both for CONFIG_ACPI set and unset without adding explicit > > compiler directives to it. > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Thanks! -- 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
