[comp.os.os2.programmer] Device Driver gurus?? Info needed on RegisterStackUsage DevHlp call

csj06895@uxa.cso.uiuc.edu (Christopher S Jones) (09/10/90)

Help!  I've been digging through manuals and debugging byte by byte, but I
still can't get the DevHlp call to RegisterStackUsage (RSU) to complete
successfully.

Summary:  My device (CSM SCSI card for MCA) uses IRQ 5 as an interrupt level.
My driver, therefore, needs to use that interrupt.  However, any time I call
RSU to register it, the carry bit always comes back set.  My Stack Usage
structure looks like this.

DS:BX ->
 length    000Eh
 int_en    0001h    I've also tried 0 here.
 IRQ_num   0005h
 nbytes1   }
 nbytes2   }        I've tried values from 10 to 200 for these.
 nbytes3   }
 max_nest  0001h    I've also tried 0 here.

I've tried calling this both before and after my call to SetIRQ (which seems to
complete fine, btw).  Should it be called before or after?

I've been debugging with OSTECH's device driver debugger line by line.  Every-
thing looks normal up to the call of DevHlp.  Then the Carry bit comes back
set.  No other error codes are available as far as I know.

Anybody have any insight.  I can't be maxing out the stack with only a ten
byte requirement can I?

Thanks for any responses.
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Chris S Jones      csj06895@uxa.cso.uiuc.edu
University of Illinois at Urbana-Champaign