Linux pays no attention to the resource consumption reported 
for legacy devices in the DSDT 
 
Each of these devices each contain _CRS specifying the IO, DMA, and IRQ 
resources consumed by the device.  For example, the mouse: 
 
                Device (PS2M) 
                { 
                    Name (_HID, EisaId ("PNP0F03")) 
                    Name (_CID, 0x130FD041) 
                    Method (_STA, 0, NotSerialized) 
                    { 
                        ShiftLeft (0x01, 0x0C, Local0) 
                        If (And (IOST, Local0)) 
                        { 
                            Return (0x0F) 
                        } 
 
                        If (OSFL ()) 
                        { 
                            Return (0x0B) 
                        } 
                        Else 
                        { 
                            Return (0x00) 
                        } 
                    } 
 
                    Name (CRS1, ResourceTemplate () 
                    { 
                        IRQNoFlags () {12} 
                    }) 
                    Name (CRS2, ResourceTemplate () 
                    { 
                        IO (Decode16, 0x0060, 0x0060, 0x00, 0x01) 
                        IO (Decode16, 0x0064, 0x0064, 0x00, 0x01) 
                        IRQNoFlags () {12} 
                    }) 
                    Method (_CRS, 0, NotSerialized) 
                    { 
                        ShiftLeft (0x01, 0x0A, Local0) 
                        If (And (IOST, Local0)) 
                        { 
                            Return (CRS1) 
                        } 
                        Else 
                        { 
                            Return (CRS2) 
                        } 
                    } 
                } 
 
There are three potential benefits to mining this information. 
1. correct resource values can be used. 
    For legacy devices with hard-coded values, this 
    'ain't broke, so don't fix it'. 
    However, if additional resources are added to the motherboard, 
    this method would recognized that while the hard-coded drivers 
    would not. 
 
2. resource conflicts can be avoided. 
    Again, Linux already skirts this issue by other methods. 
    We'll come re-open this bug only when those methods 
    start to fail... 
 
3. free resources can be freed. 
    In the example above, if the PS2 mouse is not present, 
    the OS could realized, for example, that IRQ12 is available 
    for other uses.  This could be useful on a PIC-mode IRQ-starved 
    system.... 
 
Here are the other south bridge devices listed in the DSDT for my D875PBZ: 
 
            Device (SBRG) 
                Device (PIC) 
                    Name (_HID, EisaId ("PNP0000")) 
                Device (DMAD) 
                    Name (_HID, EisaId ("PNP0200")) 
                Device (TMR) 
                    Name (_HID, EisaId ("PNP0100")) 
                Device (RTC0) 
                    Name (_HID, EisaId ("PNP0B00")) 
                Device (PS2K) 
                    Name (_HID, EisaId ("PNP0303")) 
                Device (PS2M) 
                    Name (_HID, EisaId ("PNP0F03")) 
                Device (SPKR) 
                    Name (_HID, EisaId ("PNP0800")) 
                Device (COPR) 
                    Name (_HID, EisaId ("PNP0C04")) 
                Device (\_SB.PCI0.SBRG.FDC0) 
                    Name (_HID, EisaId ("PNP0700")) 
                Device (\_SB.PCI0.SBRG.UAR1) 
                    Name (_HID, EisaId ("PNP0501")) 
                Device (\_SB.PCI0.SBRG.LPT) 
                    Name (_HID, EisaId ("PNP0400")) 
                Device (\_SB.PCI0.SBRG.ECP) 
                    Name (_HID, EisaId ("PNP0401")) 
                Device (SYSR) 
                    Name (_HID, EisaId ("PNP0C02")) 
                Device (FWH) 
                    Name (_HID, EisaId ("INT0800")) 
                Device (OSYS) 
                    Name (_HID, EisaId ("PNP0C02")) 
                Device (\_SB.SYSM) 
                    Name (_HID, EisaId ("PNP0C01"))