Re: [PATCH] pata_it8213: MWDMA0 is unsupported

Bartlomiej Zolnierkiewicz
2009-11-26T18:11:54Z

On Thursday 26 November 2009 07:00:11 pm Bartlomiej Zolnierkiewicz wrote:
> On Thursday 26 November 2009 06:23:18 pm Sergei Shtylyov wrote:
> > Bartlomiej Zolnierkiewicz wrote:
> >
> > >>MWDMA0 timings cannot be met with the PIIX based controller
> > >>programming interface.
> >
> > >>This change should be safe as this is how we have been doing
> > >>things in IDE it8213 host driver for years.
> >
> > >>Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> > >>---
> > >>Verified with the documentation (similar case as with pata_efar).
> >
> > > Uhhh, no...
> >
> > > Too many damn drivers.
> >
> > > Too much damn duplication.
> >
> > > Too much damn subtle differences here and there.
> >
> > > The hardware is probably fine for MWMDA0 when it comes to pata_{efar,it8213},
> > > it just not documented properly in the data sheet.
> >
> > How so with pata_efar? The active/recovery bitfields are still 2-bit
> > wide, no?
>
> Yes but when TIMEx bit is disabled we are using XFER_PIO_SLOW timings.
>
> All data sheets including original Intel ones are a complete crap when it
> comes to explicitly documenting this behavior.

OTOH all drivers set TIMEx for MWDMA0 currently.. ?

--
Bartlomiej Zolnierkiewicz