Hi Finn,

On Fri, Aug 15, 2014 at 1:46 PM, Finn Thain <[email protected]> wrote:
>
> On Thu, 14 Aug 2014, Michael Schmitz wrote:
>
>> >
>> > > > When cmd->device->borken, I assume sun3_NCR5380 inhibits PIO
>> > > > because PIO was itself expected to be problematic?
>> > > >
>>
>> The sun3 driver does set the borken flag but never uses it later - can't
>> see where it will inhibit PIO.
>
> It inhibited PIO when it forked the atari code and commented out the test
> for cmd->device->borken, to ensure that PIO would never be used here.

I see. I just tool that to mean the Sun3 driver never had trouble with
devices failing at that section, so no need to switch from DMA to PIO
(because DMA never fails).

> Hence my suggestion that PIO itself was expected was problematic. OTOH,
> PIO is used up to 128 bytes, and beyond 128 bytes if !REQ_TYPE_FS...

Up to 128 for DMA limitations - the other bit I don't understand either.

Cheers,

  Michael

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