Re: Floppy issues
Hello Gregor,
On Sat, 2025-10-25 at 12:35 +0200, Gregor Riepl wrote:
> > btw, the issue does not occur, if you open the floppy with another
> > device major/minor like: fd0h1440 (mknod /dev/fd0h1440 b 2 28).
>
> I can confirm that this works and makes the drive spin.
> Trying to dump a floppy result in lots of errors, but this may very well be a problem with the drive or the floppy disk:
>
> [Oct25 12:23] block device autoloading is deprecated and will be removed.
> [ +1.546997] I/O error, dev fd0_type7, sector 0 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +0.399763] I/O error, dev fd0_type7, sector 16 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +0.599822] I/O error, dev fd0_type7, sector 36 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +0.399816] I/O error, dev fd0_type7, sector 48 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +1.799332] I/O error, dev fd0_type7, sector 72 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +0.091780] floppy0: sector not found: track 2, head 0, sector 9, size 2
> [ +0.000066] I/O error, dev fd0_type7, sector 80 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +0.707901] I/O error, dev fd0_type7, sector 108 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +0.248209] floppy0: sector not found: track 3, head 0, sector 5, size 2
> [ +0.000061] I/O error, dev fd0_type7, sector 112 op 0x0:(READ) flags 0x84700 phys_seg 1 prio class 2
> [ +0.828954] floppy0: data CRC error: track 3, head 1, sector 7, size 2
> [ +0.199879] floppy0: data CRC error: track 3, head 1, sector 7, size 2
Please try to verify that your assumption is correct by trying a different floppy disk or drive or
testing access to the floppy drive with an operating system known to work. We should no rely on
assumptions.
> > We fixed that in T2 Linux (debugged that for a longer time .. ), the reason was
> > that the the probe __floppy_read_block_0 tries to read 1 page from disk, 8KB,
> > which was more than the derived floppy size of 8 sectors (4KB) from the minor
> > number, so the "beyond end of device" message comes up, see:
> > https://github.com/rxrbln/t2sde/blob/main/package/kernel/linux/hotfix-floppy-not-4k-pages.patch
>
> Is this common for PC floppy drives?
> Perhaps /dev/fd0 should register itself with the correct minor number instead.
FWIW, I have opened an issue in the sparclinux issue tracker to document this bug [1].
Since the standard PC floppy driver in the kernel is actively maintained [2], it's
worth sending the patch upstream for review.
Adrian
> [1] https://github.com/sparclinux/issues/issues/18
> [2] https://lkml.org/lkml/2019/7/31/771
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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