Messages in this thread | | | Subject | Re: 2.9test9-mm1 and DAO ATAPI cd-burning corrupt | From | Daniel Pittman <> | Date | Wed, 12 Nov 2003 11:04:25 +1100 |
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On Tue, 11 Nov 2003, Linus Torvalds wrote: > On Tue, 11 Nov 2003, Pascal Schmidt wrote: >> >> dd behaves strangly on the MO drive. I've tried with 2.6.0-test9 and >> the patch appended to the end of this mail. >> >> # dd if=testfile of=/dev/hde bs=4096 count=1 >> dd: writing `/dev/hde': no space left on device >> 1+0 records in >> 0+0 records out >> >> # dd if=/dev/hde of=mofile bs=4096 count=1 >> 0+0 records in >> 0+0 records out >> >> Mounting the disc read-only works, however, and I can read all the >> data on it without problems. > > Ok, that's just strange. You can't even _read_ from the raw device, > but the mount works ok? > > And you got no IO errors anywhere? I don't see why the write would > fail silently. > > I wonder whether the disk capacity is set to zero. See > drivers/ide/ide-cd.c, and in particular the > > /* Now try to get the total cdrom capacity. */ > stat = cdrom_get_last_written(cdi, (long *) &toc->capacity); > if (stat || !toc->capacity) > stat = cdrom_read_capacity(drive, &toc->capacity, > sense); > if (stat) > toc->capacity = 0x1fffff; > > and see what that says.. I really think you should start sprinkling > printk's around the thing to determine what goes on..
The '|| !toc->capacity' part of that code exists because I have a DVD drive that got zero capacity from the cdrom_get_last_written call.
The symptoms were exactly the same as above - I could mount and use the thing correctly, but the raw device was not readable at all.
Maybe cdrom_read_capacity can also return zero for some broken situations?
Daniel
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