From: CASINO_E <CASINO_E@teleline.es>
To: Jens Axboe <axboe@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: SII SATA request size limit
Date: Mon, 15 Sep 2003 17:24:05 +0200 [thread overview]
Message-ID: <d95d2d93f8.d93f8d95d2@teleline.es> (raw)
Forgive me if I'm saying something stupid but, do you mean a special
case for this controller in ide-dma.c:ide_build_dmatable()?
In this case, should not segment size and boundary be included in hwif
so we can have a generic ide_build_dmatable() without dealing
explicitly with special cases? We could initialize to the default for
most controllers and set the values for the exceptions inside each
particular driver.
----- Mensaje Original -----
De: Jens Axboe <axboe@suse.de>
Fecha: Lunes, Septiembre 15, 2003 10:47 am
Asunto: Re: SII SATA request size limit
> On Fri, Sep 12 2003, Eduardo Casino wrote:
> > Hi All,
> >
> > I had a look at the NetBSD pciide.c driver and found this
> interesting> bit of code:
> >
> > /*
> > * Rev. <= 0x01 of the 3112 have a bug that can cause data
> > * corruption if DMA transfers cross an 8K boundary. This is
> > * apparently hard to tickle, but we'll go ahead and play it
> > * safe.
> > */
> > if (PCI_REVISION(pa->pa_class) <= 0x01) {
> > sc->sc_dma_maxsegsz = 8192;
> > sc->sc_dma_boundary = 8192;
> > }
> >
> > This is basically the same as setting hwif->rqsize to 15, but
> the NetBSD
>
> You can do much much better than that, it's pretty simply to just
> restrict the segment size and boundary if you have a controller with
> such a bug. And then you get the benefit of the larger requests too,
> it's basically not a performance hit at that point.
>
> --
> Jens Axboe
>
>
next reply other threads:[~2003-09-15 15:24 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-15 15:24 CASINO_E [this message]
2003-09-15 15:32 ` SII SATA request size limit Jens Axboe
2003-09-15 16:00 ` Justin Cormack
2003-09-15 16:07 ` Jens Axboe
2003-09-15 22:19 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2003-09-18 17:43 Allen Martin
2003-09-15 16:33 CASINO_E
2003-09-14 0:57 Eduardo Casino
2003-09-13 16:43 Marcelo Penna Guerra
2003-09-12 23:07 Marcelo Penna Guerra
2003-09-12 23:16 ` Alan Cox
2003-09-12 21:00 Marcelo Penna Guerra
2003-09-12 22:28 ` Alan Cox
2003-09-12 20:55 Marcelo Penna Guerra
2003-09-13 10:56 ` Witold Krecicki
2003-09-12 20:48 Eduardo Casino
2003-09-15 8:47 ` Jens Axboe
2003-09-12 2:57 Marcelo Penna Guerra
2003-09-12 10:41 ` Alan Cox
2003-09-12 17:46 ` Witold Krecicki
2003-09-15 10:12 ` Adam Jones
2003-09-18 11:44 ` Witold Krecicki
2003-09-15 5:57 ` Catalin BOIE
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