Re: How's the nforce4 support in Linux?

[Richard B. Johnson]

On Tue, 5 Apr 2005, Julien Wajsberg wrote:

> On Apr 5, 2005 4:10 PM, Richard B. Johnson <linux-os@xxxxxxxxxxxx> wrote:
> > On Tue, 5 Apr 2005, Julien Wajsberg wrote:
> >
> > > On Mar 26, 2005 12:59 AM, Julien Wajsberg <julien.wajsberg@xxxxxxxxx> wrote:
> > > > I own an Asus A8N-Sli motherboard with the Nforce4-Sli chipset, and I
> > > > experiment the following problem :
> > > >
> > > > Mar 25 22:42:55 evenflow kernel: hda: dma_timer_expiry: dma status == 0x60
> > > > Mar 25 22:42:55 evenflow kernel: hda: DMA timeout retry
> > > > Mar 25 22:42:55 evenflow kernel: hda: timeout waiting for DMA
> > > > Mar 25 22:42:55 evenflow kernel: hda: status error: status=0x58 {
> > > > DriveReady SeekComplete DataRequest }
> > > > Mar 25 22:42:55 evenflow kernel:
> > > > Mar 25 22:42:55 evenflow kernel: ide: failed opcode was: unknown
> > > > Mar 25 22:42:55 evenflow kernel: hda: drive not ready for command
> > > > Mar 25 22:42:55 evenflow kernel: hda: status timeout: status=0xd0 { Busy }
> > > > Mar 25 22:42:55 evenflow kernel:
> > > > Mar 25 22:42:55 evenflow kernel: ide: failed opcode was: unknown
> > > > Mar 25 22:42:55 evenflow kernel: hdb: DMA disabled
> >                                       ^^^^^^^^^^^^^^^^^
> > > > Mar 25 22:42:55 evenflow kernel: hda: drive not ready for command
> > > >
> > > > Of course, if I disable DMA with hdparm, this problem disappear.. but
> > > > it isn't a long-term solution ;-)
> >
> > The long-term solution is to replace either the drive, cable, or the
> > motherboard that can't do DMA.
> It's a recent drive that did ultra DMA on another motherboard, and a
> recent motherboard with a cable that did ultra DMA before.It was ultra
> DMA2 on this old motherboard, but it still was ultra DMA.
>
> > A bad DMA operation can write data
> > anywhere (right into the middle of the kernel). There isn't
> > anything software can do about it. Software sets up the
> > controller for a DMA operation, then waits for an interrupt
> > that tells it has completed or failed. Software can retry failed
> > operations until software gets destroyed by the hardware, but
> > there isn't anything else that can be done.
> >
> > The fact that disabling DMA makes the problem(s) go away is
> > proof that it isn't a software problem. There are flash-RAM
> > devices that emulate IDE drives. Most of these can't do DMA
> > and the IDE driver doesn't accept that fact. That is a known
> > bug. One needs to use hdparm to tell it to stop trying to
> > use DMA. In your case, the driver stopped using DMA when
> > it found out that it didn't work. There is no bug.
>
> In my case, the driver stopped for hdb, that is my dvd-burner/player.
> It did nothing for hda or hdc, I had to disable DMA myself.
>
> Will I have to install Windows XP to prove ultra DMA works correctly
> on this setup ? I really don't hope...

How would you know?  Windows will just run it as PIOW and be done
with it. Did you ever try to copy a large file in XP? Try it.
Try the same thing in linux on the same hardware. You don't need
a stop-watch. On Win-XP, a 10 megabyte file (hardly large) takes
about 10 seconds. That's 1 megabyte/second. Linux tries to be
a bit faster.

> --
> Julien

Cheers,
Dick Johnson
Penguin : Linux version 2.6.11 on an i686 machine (5537.79 BogoMips).
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