Buffer I/O error on device sr0

[Zoltan Boszormenyi]

Justin Conover írta:
> Seeing the following in dmesg referring to my dvd drive when I try and 
> play something:
>
> end_request: I/O error, dev sr0, sector 205572
> Buffer I/O error on device sr0, logical block 51393
> Buffer I/O error on device sr0, logical block 51394
> Buffer I/O error on device sr0, logical block 51395
> Buffer I/O error on device sr0, logical block 51396
> Buffer I/O error on device sr0, logical block 51397
> Buffer I/O error on device sr0, logical block 51398
> Buffer I/O error on device sr0, logical block 51399
> Buffer I/O error on device sr0, logical block 51400
> Buffer I/O error on device sr0, logical block 51401
> Buffer I/O error on device sr0, logical block 51402

Do you also get scary messages about hardware errors, too,
like CRC errors during DMA transfer? If not, then your disk
may be broken or just dusty. Look for small spot(s) on the
data side, you may wash it off with warm soapy water :-)
However if you get CRC errors in the log too, I have to tell that
I got similar errors when booting the Fedora 8 install disk.
I had to work it around with using the "libata.dma=1" option
on boot. This only enables DMA for harddisks but not for
ATAPI devices. My ODD is a Pioneer 111 reflashed to
the Buffalo 1.28 firmware  so it can burn Labelflash labels, too.
The downside is that it reports max. usable UDMA66 about itself
but I had to limit it to UDMA44 to have stable DMA transfer despite
using an 80-wire cable. It worked on Fedora 6 with "hdparm -X67"
but now Fedora 8 doesn't allow the same with pseudo-SCSI devices. :-(
However, replacing my IDE cable with another also 80-wire one
seems to have fixed it, at least the same F-8 DVD that produced
errors during installation with DMA, now it can be read back
entirely. (To re-enable DMA, initrd had to be rebuilt with
"options libata dma=1" commented out in modprobe.conf.)