[MPlayer-users] Rescuing a scratched DVD

[Adam Nielsen]

> I have found out that my Linux kernel likes to disable DMA when a
> read error occurs and I have to manually use hdparm to re-enable 
> it again. And this can only be done after all IO has completed,
> I usually have to wait a while an look at the logs that tells me
> that a certain sector/whatever of the disc was problematic. And
> this takes a lot of time and is generally a PITA.

Yes!!!  This is the exact problem I have (though not with dirty discs.)  If I 
pause mplayer long enough for the disc to spin down, when I unpause it the 
disc doesn't spin up again and mplayer locks, waiting for the data to come 
in.  The only way I can get out of it is to eject the disc (since I didn't 
have it mounted) but this must cause a read error because DMA gets turned off 
afterwards - and it's a real hassle having to turn it back on again *every* 
time...

I have found a workaround for the time being though - I don't pause mplayer, I 
just seek back a few minutes when I go away, so that when I get back it's 
roughly in the same spot as when I left - works like a charm this way ;-)

(and yes, if I use other programs to access the drive it spins up again when 
it should - it's just mplayer, or at least the way mplayer accesses the 
drive.)

> This is probably a generic kernel/IDE problem, but I hope someone
> knows a better solution than just wait and re-enable DMA...

Yes, I too would be very interested to know if there's a way around it.

Cheers,
Adam.