| Debugging Tools for Windows |
There are primarily two bug checks that arise in the course of debugging a SCSI miniport driver: bug check 0x77 (KERNEL_STACK_INPAGE_ERROR) and bug check 0x7A (KERNEL_DATA_INPAGE_ERROR). For full details of their parameters, see Bug Check 0x77 and Bug Check 0x7A.
Each of these bug checks indicates that a paging error has occurred. There are three main causes for these bug checks:
To determine the precise cause of the failure, begin by using the !scsikd.classext extension, which displays information about recently failed requests, including the SRB status, SCSI status, and sense data of the request.
Storage class device 816e96b0 with extension at 816e9768
Classpnp Internal Information at 817b4008
Failed requests:
Srb Scsi
Opcode Status Status Sense Code Sector Time Stamp
------ ------ ------ ---------- -------- ------------
2a 0a 02 03 0c 00 0000abcd 23:01:07.453 Retried
28 0a 02 03 04 00 0000abcd 23:01:07.984 Retried
dt classpnp!_CLASS_PRIVATE_FDO_DATA 817b4008 –
...
In the previous example, opcode 0x2A indicates a write operation, and 0x28 indicates a read operation. The SCSI status in the example is 02, which indicates a check condition. The sense codes provide more error information.
As always, miniport driver developers are responsible for associating error codes from their hardware to the SRB status codes. Typically, timeouts are associated with SRB 0x0A, the code for a selection timeout. SRB 0x0e is typically associated with a full bus reset, but it can also be associated with controller errors.