[uClinux-dev] Re: question about Interrupt handler

Tom Walsh tom at cyberiansoftware.com
Mon Nov 26 14:27:29 EST 2001


Vladimir Vorobyov wrote:
> 
> > Fundamentally it is a bad thing to do. What if the app dies for some
> > reason?  The interrupt could be writing into someone else memory space.
> > What if one day you want to switch to a VM processor?
> 
> OK, but if I need to perform asynchronous reading:
> Buffering data within driver will be useless.
> Writing from interrupt handler happens only after application has called
> read function.
> 
> 1) application calls read
> 2) driver initializes reading sequence and returns
> 3) application does some computations
> 4) application polls driver (or calls IOCTL) to check for completion of data
> transfer and goes to 1)
> 
> how can I avoid writing to user space ?
> 

This is starting to sound more like a question as to how to design the
system itself instead of a specific problem resolution.  You seem to
have determined a strategy for how your program will interact with the
unspecified hardware and are now attempting to warp/bend uClinux around
that strategy.  I submit that your strategy itself may be flawed,
perhaps you should step back and rethink how the device will
interact/relate to the microprocessor and uClinux.

The solution to your design problem may be quite different than the
approach that you have decided to take, this time?

Regards,

TomW

-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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