From: Jens Axboe <axboe@suse.de>
To: Eduardo Casino <casino_e@terra.es>
Cc: linux-kernel@vger.kernel.org
Subject: Re: SII SATA request size limit
Date: Mon, 15 Sep 2003 10:47:22 +0200 [thread overview]
Message-ID: <20030915084722.GD27105@suse.de> (raw)
In-Reply-To: <1063399684.1184.7.camel@centinela>
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 prev parent reply other threads:[~2003-09-15 8:47 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-12 20:48 SII SATA request size limit Eduardo Casino
2003-09-15 8:47 ` Jens Axboe [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-09-18 17:43 Allen Martin
2003-09-15 16:33 CASINO_E
2003-09-15 15:24 CASINO_E
2003-09-15 15:32 ` Jens Axboe
2003-09-15 16:00 ` Justin Cormack
2003-09-15 16:07 ` Jens Axboe
2003-09-15 22:19 ` Alan Cox
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 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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