Problems with reading DVD-RW media

Problems with reading DVD-RW media

[Max Dmitrichenko]

Hi!

I've recently bought a new DVD-RW NEC ND-4551A device. First thing I did was
burning of two ISO images with stable Debian onto DVD-RW media. After these
images have been burned I've checked the MD5 sums and they were correct. But
now when I'm trying to read some files I've got Input/Output error. After I
load the disc into the drive, kernel begins to show error message every
second. The contents of this message is:

hdc: packet command error: status=0x51 { DriveReady SeekComplete Error }
hdc: packet command error: error=0x54 { AbortedCommand LastFailedSense=0x05 }
ide: failed opcode was: unknown

Some goggling showed that this could be DMA problem. But disabling DMA didn't
give any results.

The interest thing is that readcd still produces a valid image from this disc
and it has correct MD5 sum. So the problem is not in the media. Furthermore,
the disc can be perfectly read from Win2K in the VMWare environment when host
OS is my linux and independent of DMA settings.

Currently I'm running kernel 2.6.15. But this problem was noticed in 2.6.12 too.
The mainboard has i815 chipset.

Any idea what's wrong? Does anybody get this error too?

--
  Maxim Dmitrichenko

Re: Problems with reading DVD-RW media

[Krzysztof Halasa]

Max Dmitrichenko <dmitrmax@rain.ifmo.ru> writes:

> The interest thing is that readcd still produces a valid image from this disc
> and it has correct MD5 sum. So the problem is not in the media. Furthermore,
> the disc can be perfectly read from Win2K in the VMWare environment when host
> OS is my linux and independent of DMA settings.

Read-ahead + number of sectors not set I'd bet. Padding the image with
some amount of empty sectors would probably help.

I.e., the discs are ok, the read procedure is faulty.
-- 
Krzysztof Halasa