I'm trying to get portcls.sys to shed some light on why KsStudio fails to
instantiate a filter on a custom, portcls-based midi miniport driver. The
driver shows up in "DevMgr->Sound, video and game controllers" but when I
attempt to instantiate the render or capture filter using KsStudio, I get:
OpenFilter() - Failed to open device xxxx\mycustommididriver.
[GetLastError() returned 0 (0x0) The operation completed successfully. ]
Using windbg I've set a breakpoint in portcls!DispatchCreate and have
validated that the Filename in the Irp->Tail->Overlay->OriginalFileObject
is "\mycustommididriver". Additionally, I've used !object to determine
that the xxxx portion of the above device name exists in the \GLOBAL??
directory, and that its accessible and is linked to the PDO for my
miniport. My mini port's Fdo is between ksthunk (upper) and a custom
driver (lower) (PDO)
Is there a special flag that the checked portcls.sys image needs to output
debug info? I've set HKLM\system\ccs\control\session manager\Debug Print
Filter\DEFAULT = 0xffffffff and I get lots of debug spew, just none from
portcls.sys. Additionally, the Create IRP's completion status is is
0xc0000034 - STATUS_OBJECT_NAME_NOT_FOUND
Thanks.
