Debugging Tools for Windows

Checking for Resource Conflicts

This section discusses techniques that can be used to detect resource conflicts.

The first technique involves dumping the arbiter data. The following example examines the arbiter data for the I/O ranges:

kd> !arbiter 1

DEVNODE ff0daf48
  Port Arbiter "RootPort" at 8045b920
    Allocated ranges:
      10 - 1f S         Owner ff0d6b30
      22 - 3f S         Owner ff0d6b30
      44 - 47 S         Owner ff0d6b30
      4c - 6f S         Owner ff0d6b30
      72 - 7f S         Owner ff0d6b30
      90 - 91 S         Owner ff0d6b30
      93 - 9f S         Owner ff0d6b30
      a2 - bf S         Owner ff0d6b30
      d0 - ef S         Owner ff0d6b30
      100 - 2f7 S       Owner ff0d6b30
      300 - cf7 S       Owner ff0d6b30
      d00 - ffff S      Owner ff0d6b30
    Possible allocation:
      < none >

    DEVNODE ff0d2e28 (PCI_HAL\PNP0A03\0)
      Port Arbiter "PCI I/O Port (b=00)" at e122c2c8
        Allocated ranges:
          0 - f         Owner 00000000
          20 - 21       Owner 00000000
          40 - 43       Owner 00000000
          48 - 4b       Owner 00000000
          60 - 60       Owner ff0d4030
          64 - 64       Owner ff0d4030
          70 - 71       Owner 00000000
          80 - 8f       Owner 00000000
          92 - 92       Owner 00000000
          a0 - a1       Owner 00000000
          c0 - cf       Owner 00000000
          f0 - ff       Owner 00000000
          170 - 177     Owner ff0cf030
          1ce - 1cf S   Owner ff040040
          2f8 - 2ff     Owner 00000000
          376 - 376     Owner ff0cf030
          378 - 37f     Owner ff0d4e70
          3b0 - 3bb S   Owner ff040040
          3c0 - 3cf S   Owner ff0bb900
          3c0 - 3df S   Owner ff040040
          3d4 - 3db S   Owner ff0bb900
          3de - 3df S   Owner ff0bb900
          3ec - 3ef     Owner ff0d0b50 (This device conflicts with another device, see below)
          3f2 - 3f5     Owner ff0d4770
          3f7 - 3f7 S   Owner ff0d4770
          3f8 - 3ff     Owner ff0d4af0
          778 - 77b     Owner ff0d4e70
          cf8 - cff     Owner 00000000
          1000 - 10ff           Owner ff0d1030
          1400 - 140f           Owner ff0d1d30
          1410 - 141f           Owner ff0d1890
          10000 - ffffffffffffffff      Owner 00000000
        Possible allocation:
          < none >

Note that there are two arbiters: one located in the root of the device tree, and one in PCI_HAL. Also note that the PCI arbiter claims and preallocates ranges for the devices it arbitrates (0xD000-0xFFFF, which is later suballocated by the PCI arbiter for its devices). The Owner field indicates the device object that owns the range. A value of zero for Owner indicates that the range is not on the bus. In the case of a PCI bridge, for example, all the ranges it does not pass will be assigned to NULL.

In the following example, the PCI bridge passes I/O 0xD000-0xDFFFF so its arbiter will contain the following two ranges:

0-CFFFF            Owner 00000000
E0000-FFFFFFFFFFFFFFFF   Owner 00000000

The FFFFFFFFFFFFFFFF is because all arbitrated resources are treated as 64-bit ranges.

Examples:

kd> !devobj ff0bb900

Device object (ff0bb900) is for:
 Video0 \Driver\mga_mil DriverObject ff0bbc10
Current Irp 00000000 RefCount 1 Type 00000023 Flags 0000204c
DevExt ff0bb9b8 DevNode ff0bb808
Device queue is not busy.
kd> !devnode ff0bb808

DevNode 0xff0bb808 for PDO 0xff0bb900 at level 0xffffffff
  Parent 0xff0daf48   Sibling 0000000000   Child 0000000000
  InterfaceType 0xffffffff  Bus Number 0xffffffff
  TargetDeviceNotify List - f 0xff0bb86c  b 0xff0bb86c
  Flags (0x00000400)  DNF_RESOURCE_REPORTED
kd> !devnode ff0bb808 6

DevNode 0xff0bb808 for PDO 0xff0bb900 at level 0xffffffff
  Parent 0xff0daf48   Sibling 0000000000   Child 0000000000
  InterfaceType 0xffffffff  Bus Number 0xffffffff
  TargetDeviceNotify List - f 0xff0bb86c  b 0xff0bb86c
  Flags (0x00000400)  DNF_RESOURCE_REPORTED
  CmResourceList at 0xe12474e8  Version 0.0  Interface 0x5  Bus #0
    Entry 0 - Port (0x1) Shared (0x3)
      Flags (0x01) - PORT_MEMORY PORT_IO
      Range starts at 0x3c0 for 0x10 bytes
    Entry 1 - Port (0x1) Shared (0x3)
      Flags (0x01) - PORT_MEMORY PORT_IO
      Range starts at 0x3d4 for 0x8 bytes
    Entry 2 - Port (0x1) Shared (0x3)
      Flags (0x01) - PORT_MEMORY PORT_IO
      Range starts at 0x3de for 0x2 bytes
    Entry 3 - Memory (0x3) Device Exclusive (0x1)
      Flags (0000) - READ_WRITE
      Range starts at 0x0000000040000000 for 0x4000 bytes
    Entry 4 - Memory (0x3) Device Exclusive (0x1)
      Flags (0000) - READ_WRITE
      Range starts at 0x0000000040800000 for 0x800000 bytes

As shown in the example, this operation retrieved the legacy video card that owns the range 3c0-3cf. The same device object is listed near the other ranges it owns (3de-3df and 3d4-3dc). Using the same tracking technique, the range of 3f8-3ff is determined to be that used by the serial port.

A similar technique is required to translate the interrupts:

kd> !arbiter 4

DEVNODE ff0daf48
  Interrupt Arbiter "RootIRQ" at 8045bae0
    Allocated ranges:
      31 - 31           Owner ff0d4030
      34 - 34 S         Owner ff0d4af0
      36 - 36           Owner ff0d4770
      3b - 3b S         Owner ff0d1030
      3b - 3b S         Owner ff0d1d30
      3c - 3c           Owner ff0d3c70
      3f - 3f           Owner ff0cf030
    Possible allocation:
      < none >

Note that there is a single arbiter for interrupts: the root arbiter.

For example, translate the interrupt 3F to an IRQ. First dump the device object, then the devnode:

kd> !devobj ff0cf030

Device object (ff0cf030) is for:
 IdeFdoff0d0398Channel1 \Driver\IntelIde DriverObject ff0d0530
Current Irp 00000000 RefCount 0 Type 00000004 Flags 00001040AttachedDev ff0cd030

DevExt ff0cf0e8 DevNode ff0cfe88
Device queue is not busy.
kd> !devnode ff0cfe88 6

DevNode 0xff0cfe88 for PDO 0xff0cf030 at level 0x3
  Parent 0xff0d1348   Sibling 0000000000   Child 0xff0c84a8
  InterfaceType 0xffffffff  Bus Number 0xfffffff0
  InstancePath is "PCIIDE\IDEChannel\1&1"
  ServiceName is "atapi"
  TargetDeviceNotify List - f 0xff0cfeec  b 0xff0cfeec
  Flags (0x6000120b)  DNF_PROCESSED, DNF_STARTED,
                      DNF_ENUMERATED, DNF_RESOURCE_ASSIGNED,
                      DNF_ADDED, DNF_HAS_BOOT_CONFIG
                      Unknown flags 0x40000000
  CmResourceList at 0xe12321c8  Version 0.0  Interface 0x1  Bus #0
    Entry 0 - Port (0x1) Device Exclusive (0x1)
      Flags (0x01) - PORT_MEMORY PORT_IO
      Range starts at 0x170 for 0x8 bytes
    Entry 1 - Port (0x1) Device Exclusive (0x1)
      Flags (0x01) - PORT_MEMORY PORT_IO
      Range starts at 0x376 for 0x1 bytes
    Entry 2 - Interrupt (0x2) Device Exclusive (0x1)
      Flags (0x01) - LATCHED
      Level 0xf, Vector 0xf, Affinity 0xffffffff

  IoResList at 0xe12363c8 : Interface 0x1  Bus 0  Slot 0
  Reserved Values = {0x0002e0d0, 0x00920092, 0xe1235508}
    Alternative 0 (Version 1.1)
      Preferred Descriptor 0 - NonArbitrated/ConfigData (0x80) Shared (0x3)
        Flags (0000) -
        Data:              : 0x1 0x61004d 0x680063
      Preferred Descriptor 1 - Port (0x1) Device Exclusive (0x1)
        Flags (0x01) - PORT_IO
        0x000008 byte range with alignment 0x000001
        170 - 0x177
      Preferred Descriptor 2 - Port (0x1) Device Exclusive (0x1)
        Flags (0x01) - PORT_IO
        0x000001 byte range with alignment 0x000001
        376 - 0x376
      Preferred Descriptor 3 - Interrupt (0x2) Device Exclusive (0x1)
        Flags (0x01) - LATCHED
        0xf - 0xf
    Alternative 1 (Version 1.1)
      Preferred Descriptor 0 - Port (0x1) Device Exclusive (0x1)
        Flags (0x01) - PORT_IO
        0x000008 byte range with alignment 0x000001
        170 - 0x177
      Preferred Descriptor 1 - Port (0x1) Device Exclusive (0x1)
        Flags (0x01) - PORT_IO
        0x000001 byte range with alignment 0x000001
        376 - 0x376
      Preferred Descriptor 2 - Interrupt (0x2) Device Exclusive (0x1)
        Flags (0x01) - LATCHED
        0xf - 0xf

For example, try to determine if there is a resource conflict that caused this device not to start, starting with a devnode:

kd> !devnode 0xff0d4bc8 6

DevNode 0xff0d4bc8 for PDO 0xff0d4cb0 at level 0
  Parent 0xff0daf48   Sibling 0xff0d4a08   Child 0000000000
  InterfaceType 0xffffffff  Bus Number 0xffffffff
  InstancePath is "Root\*PNP0501\1_0_17_2_0_0"
  ServiceName is "Serial"
  TargetDeviceNotify List - f 0xff0d4c2c  b 0xff0d4c2c
  Flags (0x60001129)  DNF_PROCESSED, DNF_ENUMERATED,
                      DNF_MADEUP, DNF_INSUFFICIENT_RESOURCES,
                      DNF_ADDED, DNF_HAS_BOOT_CONFIG
                      Unknown flags 0x40000000

  IoResList at 0xe1251e28 : Interface 0x1  Bus 0  Slot 0
  Reserved Values = {0x0043005c, 0x006e006f, 0x00720074}
    Alternative 0 (Version 1.1)
      Preferred Descriptor 0 - NonArbitrated/ConfigData (0x80) Undetermined Shar
ing (0)
        Flags (0000) -
        Data:              : 0xc000 0x0 0x0
      Preferred Descriptor 1 - Port (0x1) Undetermined Sharing (0)
        Flags (0x05) - PORT_IO 10_BIT_DECODE
        0x000008 byte range with alignment 0x000001
        3e8 - 0x3ef
      Preferred Descriptor 2 - Interrupt (0x2) Shared (0x3)
        Flags (0x01) - LATCHED
        0x5 - 0x5
    Alternative 1 (Version 1.1)
      Preferred Descriptor 0 - NonArbitrated/ConfigData (0x80) Undetermined Shar
ing (0)
        Flags (0000) -
        Data:              : 0xc000 0x0 0x0
      Preferred Descriptor 1 - Port (0x1) Undetermined Sharing (0)
        Flags (0x05) - PORT_IO 10_BIT_DECODE
        0x000008 byte range with alignment 0x000008
        3e8 - 0x3ef
      Preferred Descriptor 2 - Interrupt (0x2) Shared (0x3)
        Flags (0x01) - LATCHED
        0x5 - 0x5

First, make the assumption that this is an I/O conflict and dump the arbiters (see the preceding example). The result shows that the range 0x3EC-0x3EF is owned by 0xFF0D0B50, which overlaps the serial device's resources request. Next, dump the device object for the owner of this range, and then dump the devnode for the owner:

kd> !devobj ff0d0b50

Device object (ff0d0b50) is for:
 Resource00413e \Driver\isapnp DriverObject ff0d0e10
Current Irp 00000000 RefCount 0 Type 00000004 Flags 00001040
DevExt ff0d0c08 DevNode ff0d0a68
Device queue is not busy.
kd> !devnode ff0d0a68 6

DevNode 0xff0d0a68 for PDO 0xff0d0b50 at level 0xffffffff
  Parent 0xff0daf48   Sibling 0000000000   Child 0000000000
  InterfaceType 0xffffffff  Bus Number 0xffffffff
Duplicate PDO 0xff0d0e10  TargetDeviceNotify List - f 0xff0d0acc  b 0xff0d0acc
  Flags (0x00000421)  DNF_PROCESSED, DNF_MADEUP,
                      DNF_RESOURCE_REPORTED
  CmResourceList at 0xe1233628  Version 0.0  Interface 0x1  Bus #0
    Entry 0 - Port (0x1) Device Exclusive (0x1)
      Flags (0x01) - PORT_MEMORY PORT_IO
      Range starts at 0x3ec for 0x4 bytes

This is a "pseudo-devnode" that corresponds to the range allocated by the ISAPNP driver for its read data port.

To determine the resources that the PnP Manager assigned to a particular device when it attempted to start the device:

  1. Place a breakpoint on the routine that is called when the IRP_MN_START_DEVICE request is received by the driver. You can also place a breakpoint on the driver's dispatch routine (if you know its name). In both cases, the driver and its symbols should be loaded. This may require you to set an initial breakpoint.

    For example, for PCMCIA you can set a breakpoint on pcmcia!pcmciastartpccard. The advantage of using this particular routine is that its second parameter is a CM Resource List that you can dump using !cmreslist (eliminating step 3). See the following PCMCIA example.

  2. When you have determined which device is of interest, dump the device object (if you have not done so already), and then dump the devnode with the CM Resource List. Check which resources were assigned to the device. You may also check whether the resources are a subset of the I/O Resource List. Then type g or single step through the procedure, and determine whether the device was started and which resources were assigned. If a device was offered a set of resources to start but failed to do so, the driver might not be behaving properly (for example, if it incorrectly declared that it can use a set of resources it cannot actually use).

Example:

ntoskrnl!IopStartDevice:
80420212 55               push    ebp
kd> kb
ChildEBP RetAddr  Args to Child
f64138c0 8048b640 ff0ce870 ff0d7c08 ff0cde88 ntoskrnl!IopStartDevice (!devobj ff0ce870)
f64138f0 8048d8e7 ff0cde88 f6413978 ff0cddc8 ntoskrnl!IopStartAndEnumerateDevice
+0x1a
f6413900 8048de7f ff0cde88 f6413978 ff0cf448 ntoskrnl!IopProcessStartDevicesWork
er+0x43
f6413910 8048d8d5 ff0cf448 8048d8a4 f6413978 ntoskrnl!IopForAllChildDeviceNodes+
0x1f
f6413924 8048de7f ff0cf448 f6413978 ff0d3f48 ntoskrnl!IopProcessStartDevicesWork
er+0x31
f6413934 8048d8d5 ff0d3f48 8048d8a4 f6413978 ntoskrnl!IopForAllChildDeviceNodes+
0x1f
f6413948 8048d893 ff0d3f48 f6413978 e12052e8 ntoskrnl!IopProcessStartDevicesWork
er+0x31
f641395c 804f6f1b ff0d7c08 f6413978 8045c520 ntoskrnl!IopProcessStartDevices+0x1
f
f64139d0 804f5cc1 80088000 f6413aec 8045bba0 ntoskrnl!IopInitializeBootDrivers+0
x2f9
f6413b24 804f4db3 80088000 00000001 00000000 ntoskrnl!IoInitSystem+0x3a6
f6413da8 80447610 80088000 00000000 00000000 ntoskrnl!Phase1Initialization+0x6a3

f6413ddc 8045375a 804f4710 80088000 00000000 ntoskrnl!PspSystemThreadStartup+0x5
4
00000000 00000000 00000000 00000000 00000000 ntoskrnl!KiThreadStartup+0x16
kd> !devobj ff0ce870

Device object (ff0ce870) is for:
 NTPNP_PCI0002 \Driver\PCI DriverObject ff0ceef0
Current Irp 00000000 RefCount 0 Type 00000022 Flags 00001040AttachedDev ff0cb9e0

DevExt ff0ce928 DevNode ff0cde88
Device queue is not busy.
kd> !devnode ff0cde88 6

DevNode 0xff0cde88 for PDO 0xff0ce870 at level 0x2
  Parent 0xff0cf448   Sibling 0xff0cddc8   Child 0000000000
  InterfaceType 0xffffffff  Bus Number 0xffffffff
  InstancePath is "PCI\VEN_8086&DEV_7010\0&69"
  ServiceName is "intelide"
  TargetDeviceNotify List - f 0xff0cdeec  b 0xff0cdeec
  Flags (0x00001209)  DNF_PROCESSED, DNF_ENUMERATED,
                      DNF_RESOURCE_ASSIGNED, DNF_ADDED 
                      (note that the device is not yet started)
  CmResourceList at 0xe120fce8  Version 0.0  Interface 0x5  Bus #0
    Entry 0 - Port (0x1) Device Exclusive (0x1)
      Flags (0x01) - PORT_MEMORY PORT_IO
      Range starts at 0xfff0 for 0x10 bytes (these are the resources used: 0xfff0-0xffff)
    Entry 1 - DevicePrivate (0x81) Device Exclusive (0x1)
      Flags (0000) -
      Data - {0x00000001, 0x00000004, 0000000000}

  IoResList at 0xe120df88 : Interface 0x5  Bus 0  Slot 0x2d
    Alternative 0 (Version 1.1)
      Descriptor 0 - Port (0x1) Device Exclusive (0x1)
        Flags (0x01) - PORT_IO
        0x000010 byte range with alignment 0x000010
        0 - 0xffff     (it could have used any 16 bytes that are 16-byte aligned between 0 and 0xffff)
      Descriptor 1 - DevicePrivate (0x81) Device Exclusive (0x1)
        Flags (0000) -
        Data:              : 0x1 0x4 0x0

Example for PCMCIA:

kd> bp pcmcia!pcmciastartpccard
Loading symbols for 0x8039d000       pcmcia.sys ->   pcmcia.sys
kd> kb
Loading symbols for 0x80241000         ndis.sys ->   ndis.sys
ChildEBP RetAddr  Args to Child
f6413814 803a7cbd ff0d0c30 e11d8808 ff0d0c30 pcmcia!PcmciaStartPcCard 
f6413838 803a3798 ff0d0c30 ff0d1500 ff0d1588 pcmcia!PcmciaPdoPnpDispatch+0x169
f6413848 80418641 ff0d0c30 ff0d1588 00000000 pcmcia!PcmciaDispatch+0x3a
f641385c 802455cf ff0d1614 ff0d1638 00040000 ntoskrnl!IofCallDriver+0x35
f641387c 802497cf ff0d1588 ff0d0c30 ff0c8210 NDIS!ndisPassIrpDownTheStack+0x3b
f64138ac 80418641 ff0c8210 ff0d161c ff0d1640 NDIS!ndisPnPDispatch+0x1f9
f64138c0 8048de68 ff0c3508 ff0d16a8 00000000 ntoskrnl!IofCallDriver+0x35
f64138d4 8041ff5e ff0c8210 f64138f8 ff0c3508 ntoskrnl!IopAsynchronousCall+0x90
f6413920 8048b4ae ff0d0c30 ff0e0a68 ff0d16a8 ntoskrnl!IopStartDevice+0x76
f6413950 8048d707 ff0d16a8 f64139fc 00000000 ntoskrnl!IopStartAndEnumerateDevice+0x1a
f6413960 8048dc9f ff0d16a8 f64139fc ff0d1e88 ntoskrnl!IopProcessStartDevicesWorker+0x43
f6413970 8048d6f5 ff0d1e88 8048d6c4 f64139fc ntoskrnl!IopForAllChildDeviceNodes+0x1f
f6413984 8048dc9f ff0d1e88 f64139fc ff0d3268 ntoskrnl!IopProcessStartDevicesWorker+0x31
f6413994 8048d6f5 ff0d3268 8048d6c4 f64139fc ntoskrnl!IopForAllChildDeviceNodes+0x1f
f64139a8 8048dc9f ff0d3268 f64139fc ff0d7b28 ntoskrnl!IopProcessStartDevicesWorker+0x31
f64139b8 8048d6f5 ff0d7b28 8048d6c4 f64139fc ntoskrnl!IopForAllChildDeviceNodes+0x1f
f64139cc 8048d6b3 ff0d7b28 f64139fc 80087000 ntoskrnl!IopProcessStartDevicesWorker+0x31
f64139e0 804f6c97 ff0e0a68 f64139fc 8045c140 ntoskrnl!IopProcessStartDevices+0x1f
f6413a30 804f5601 000001e0 80087000 00000000 ntoskrnl!IopInitializeSystemDrivers+0x5b
f6413b7c 804f4820 80087000 00000001 00000000 ntoskrnl!IoInitSystem+0x3fe
kd> !cmreslist e11d8808

CmResourceList at 0xe11d8808  Version 0.0  Interface 0x1  Bus #0
  Entry 0 - Interrupt (0x2) Device Exclusive (0x1)
    Flags (0x01) - LATCHED
    Level 0x9, Vector 0x9, Affinity 0xffffffff
  Entry 1 - Port (0x1) Device Exclusive (0x1)
    Flags (0x01) - PORT_MEMORY PORT_IO
    Range starts at 0xdfe0 for 0x20 bytes (started with IRQ 9, IO dfe0-dfff)
  Entry 2 - DevicePrivate (0x81) Device Exclusive (0x1)
    Flags (0000) -
    Data - {0x00010120, 0000000000, 0000000000}

kd> g 

Build machine: CAPEBUILD