Subject: Re: ATA/ATAPI kernel redesign
To: None <tech-kern@netbsd.org>
From: Lloyd Parkes <lloyd@must-have-coffee.gen.nz>
List: tech-kern
Date: 02/24/2002 14:33:38
> I've been thinking about this for some time yet, and there is no need to
> separate the drivers.

I disagree. We currently have code in wdc.c that does things to ATA devices 
that vary from merely not recommended to strictly forbidden. I want NetBSD to 
have the best quality ATA/ATAPI driver that it can, and I believe that we need 
to shed much of the old WDC code to do this.

> ..., or
> brokeness of the ATA specs (like the 30s delay after a reset).

This raises another point. We don't wait for 30s after a reset, and we 
shouldn't be doing resets (according to the bit if the spec that I recall). I 
don't mind waiting 30s for a disk to spin up, it's certainly better than some 
systems that have had to publish workarounds because they try and boot from 
disks that haven't spun up yet.

> Ripping out this code would probably break some ATA hardware.

I do not want to remove any code that is needed to support any device that 
identifies itself as either ATA or ATAPI. I expect that some older ATA devices 
don't identify themselves as ATA, but they can still be driven by the old WDC 
code.

> I've been thinking about delaying the probe of ATA devices after inetrupts
> enable (like SCSI) exept for non-direct busses (should be only ISA).

That shouldn't be necessary, but if it makes something else easier, I certainly won't argue against it.

Cheers,
Lloyd