Re: Kernel Summit request for Discussion of future of ATA (libata)and IDE

[Sergei Shtylyov]

Hello, I wrote:
> > > > > supported. I couldn't track down where that bit was actually 
> > > > > defined in the first place, all the way back to ATA-1 it seems to 
> > > > > be indicated as reserved. Actually, I'm not sure why the drive 
> > > > > cares in the first place, it would seem like a pure host 
> > > > > controller issue..
> > > > >             
> > > > It goes back before IDE into the depths of the original compaq 
> > > > spec. When
> > > > you have a device wired basically directly to the ISA bus (original 
> > > > IDE)
> > > >         
> > >    ISA has only 8/16-bit data bus, so it could not have mattered 
> > > there...     
> >
> > Depends what a 32bit I/O looks like on the 16bit bus - timing wise.
> >   
>
>   Two 16-bit reads at addresses 0x1x0 and 0x1x2 with the programmed 
> recovery time, IIRC... It's just occured to me that in case of the 
> 16-bit bus it should be how the drive treated the accesses at address 
> 0x1x2 with IOCS16 asserted that could have mattered. If it honored 
> them, 32-bit I/O could have worked even on a dumb ISA "controller", if 
> not -- no way (unless you really had *something* between the ISA and 
> the IDE cable).

   Oh, -IOCS16 is driven by device, not host. I give up then. :-)

MBR, Sergei


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