svn commit: r185059 - in head/sys: dev/acpica dev/sio isa kern

[John Baldwin]

On Tuesday 18 November 2008 04:01:54 pm John Baldwin wrote:
> Author: jhb
> Date: Tue Nov 18 21:01:54 2008
> New Revision: 185059
> URL: http://svn.freebsd.org/changeset/base/185059
> 
> Log:
>   Allow device hints to wire the unit numbers of devices.
>   - An "at" hint now reserves a device name.
>   - A new BUS_HINT_DEVICE_UNIT method is added to the bus interface.  When
>     determining the unit number of a device, this method is invoked to
>     let the bus driver specify the unit of a device given a specific
>     devclass.  This is the only way a device can be given a name reserved
>     via an "at" hint.
>   - Implement BUS_HINT_DEVICE_UNIT() for the acpi(4) and isa(4) bus drivers.
>     Both of these busses implement this by comparing the resources for a
>     given hint device with the resources enumerated by ACPI/PnPBIOS and
>     wire a unit if the hint resources are a subset of the "real" resources.
>   - Use bus_hinted_children() for adding hinted devices on isa(4) busses
>     now instead of doing it by hand.
>   - Remove the unit kludging from sio(4) as it is no longer necessary.

Effectively this means that 'hint.uart.0.port=0x3f8' will wire 'uart0' to be 
the serial port with an I/O port address of '0x3f8', even if it is not the 
first serial port ACPI enumerates.  This should mostly be a nop.  However, it 
should help machines where ACPI enumerates COM2 before COM1.  With the 
default hints, COM1 will now always be sio0/uart0, even if ACPI enumerates 
COM2 first.

-- 
John Baldwin