Re: ide-cd turning off DMA when verifying DVD-R

["Ville Syrjälä" <syrjala@sci.fi>]

On Thu, 12 Jan 2006 22:35:21 +0100, Ondrej Zary wrote:

> Hello,
> I found this problem when burning DVDs using K3b (it uses growisofs to 
> do the work) with LG GSA-4167B drive:
> Burn process completes without any problems, then K3b ejects and reloads 
> the tray, then it calculates MD5 checksum from the image. Then it starts 
> reading the DVD back to calculate MD5 checksum of it. The moment it 
> starts to read, this appears in dmesg:
> 
> hdd: irq timeout: status=0xd0 { Busy }
> ide: failed opcode was: unknown
> hdd: DMA disabled
> hdd: ATAPI reset complete
> 
> And then it slowly reads the DVD in PIO mode. After about a hour, it 
> finishes with success. When I re-enable DMA mode ("hdparm -d1 /dev/hdd") 
> immediately after it was disabled, it works fine in - there are no more 
> errors in the log and the verification completes much sooner. I burnt 10 
> DVDs and it always does exactly this.
> 
> Any ideas why it does this? And why ide-cd disables the DMA?

I think the drive just takes too long to recongize the disc. My 4163B has
the same problem which is why I always close the tray manually or with
eject -t and wait a while before mounting or burning the disc. Of course
that won't help in your case. I guess the real fix would be to
increase some ide-cd timeout.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/