Subject: Re: putting functionality in firmware vs OS
To: Parag Patel <parag@cgt.com>
From: Jason Thorpe <thorpej@nas.nasa.gov>
List: tech-kern
Date: 07/30/1998 10:36:06
On Wed, 29 Jul 1998 21:34:51 -0700 
 Parag Patel <parag@cgt.com> wrote:

 > It's pretty slow because OpenFirmware is designed around a polling-only
 > driver architecture but it can be (and has been) done.  Most FCode
 > drivers are fairly dumb as they cannot rely on interrupts which are
 > system dependent, and OF doesn't specify how to deal with them.

Indeed; running OpenFirmware drivers only on my Shark is VERY SLOW :-)

 > PCI is pretty easy to re-probe if you're not looking to allocate BARs or
 > load FCode ROMs.  USB and Firewire look much nastier, especially with
 > their hot-plug features.  The OS ends up needing a pretty complete set
 > of configuration code but the firmware also needs to do this to figure
 > out where to boot from and what device to use as the console.

...well, there is hot-plug PCI :-)

Jason R. Thorpe                                       thorpej@nas.nasa.gov
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