Re: A CD with errors (scratches etc.) blocks the whole system while reading damadged files

[Hans-Peter Jansen]

On Fri, 19 Apr 2002 14:01:13 -0600
"Erik Andersen" <[e-mail]> wrote:

> This should help somewhat.  Currently, ide-cd.c retries ERROR_MAX
> (8) times when it sees an error.  But ide.c is also retrying
> ERROR_MAX times when _it_ sees an error, and does a bus reset
> after evey 4 failures.  So for each bad sector, you get 64
> retries (with typical timouts of 7 seconds each) plus 16 bus
> resets per bad sector.

Thanks for investigation. BTW: Does this cover the ide-scsi case, too?
 
> The funny thing is though, we knew after the first read that we
> had an uncorrectable medium error.  Try this patch vs 2.4.19-pre7
> 
> --- linux/drivers/ide/ide-cd.c.orig	Tue Apr  9 06:59:56 2002
> +++ linux/drivers/ide/ide-cd.c	Tue Apr  9 07:04:59 2002
> @@ -657,6 +657,11 @@
>  			   request or data protect error.*/
>  			ide_dump_status (drive, "command error", stat);
>  			cdrom_end_request (0, drive);
> +		} else if (sense_key == MEDIUM_ERROR) {
> +			/* No point in re-trying a zillion times on a bad 
> +			 * sector...  If we got here the error is not correctable */
> +			ide_dump_status (drive, "media error (bad sector)", stat);

.. and some curious will want to know which sector has thrown the error 
[which would save me to patch this some day myself...]

> +			cdrom_end_request (0, drive);
>  		} else if ((err & ~ABRT_ERR) != 0) {
>  			/* Go to the default handler
>  			   for other errors. */
>  -Erik
> 
> --
> Erik B. Andersen             http://codepoet-consulting.com/
> --This message was written using 73% post-consumer electrons--

Cheers,
  Hans-Peter