Re: disk corruptions on "tuned" disks Was: APM killing low-latency performance on BX mainboard

Jens Axboe (axboe@image.dk)
Thu, 11 Nov 1999 13:22:29 +0100


On Wed, Nov 10 1999, Andre Hedrick wrote:
> > > Put any CDROM/DVD in DMA mode and it will work
> > > for a while and then eventually lock the PC up. This is a hardware flaw.
>
> Maybe the kernel is not up to clean DVD support with DMAing, I need to get
> a DVD drive to do fixes and kludges per chipset......

I think that is only a problem with that specific VIA chipset.
I have sucessfully run UDMA the one DVD drive I have that
supports UDMA. Works like a charm. And fast too :)

> > PS: why should recent ATAPI CDROM let you set the DMA mode, when they
> > know that it could lead to problems ?
>
> Many of them work, all three of mine do.

Of the four ATAPI drives I have in my machine right now, three
will do DMA and the last does UDMA. I have seen ATAPI drives
report DMA capabilities and then fail miserably anyway.
Especially the earlier+cheaper models reported DMA, but
didn't work at all. Blaim the hardware.

-- 
*  Jens Axboe <axboe@image.dk>
*  Linux CD-ROM Maintainer
*  http://www.kernel.dk

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