Duration of Blocked Interrupts

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On Tue, 28 Apr 1998, Doug Ledford wrote:

> Justin T. Gibbs wrote:
> > First of all, excuse my ignorance of Linux kernel internals.  I'm
> > a FreeBSD hacker by trade...  But, I believe that Linux has what
> > is called a "bottom half handler" which is somewhat similar to a
> > software interrupt handler that can be preempted by other interrupts.
> 
> There is one for the network devices already.  There isn't one for the SCSI
> drivers.  If you want one, you have to build it yourself.

I've finally had a chance to investigate this a little more and I'm
curious about this.  I've found a SCSI_BH and scsi_bottom_half_handler (in
scsi.c) that look like they perform the exact function specified (delayed 
processing of completed commands). 

It appears as though simply setting use_new_eh_code to 1 in the AIC7XXX
macro will cause the bottom half to be enabled.  All of this is from a
cursory perusal of the code so I'd appreciate any further information
anyone might have on this subject. 

Thanks,
  Robert


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