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From: Wim Osterholt <wim@djo.tudelft.nl>
To: jikos@kernel.org
Cc: Wim Osterholt <wim@djo.tudelft.nl>, linux-kernel@vger.kernel.org
Subject: disfunctional floppy driver in kernels 4.5, 4.6 and 4.7
Date: Sat, 11 Jun 2016 01:02:55 +0200	[thread overview]
Message-ID: <20160610230255.GA27770@djo.tudelft.nl> (raw)

L.S.

up to vanilla kernel 4.4.13 floppy functionality performs like it should.
(On an x86 PC that is. With a 1.44MB diskette drive.)
>From kernel 4.5* and up it changed to barely usable.

After a virgin start (cold or warm boot) with an empty diskette drive and
then loaded with a standard 720K diskette you may run 'mdir' (from mtools)
and it shows the directory fine.
The first time you load a standard 1.44MB diskette (wether it is a virgin
start or after a 720K disktette) and you run mdir, it says literally:

 plain_io: Input/output error
 init A: could not read boot sector
 Cannot initialize 'A:'

After this, all subsequent runs of mdir will do fine on both floppies.
However, most of my floppies are in a different format. (1.6MB)
I rely on 'setfdprm' (from fdutils) to set the correct parameters.

setfdprm /dev/fd0 1600/1440
/dev/fd0: Invalid argument

Strace shows me:
...
open(/dev/fd0, O_ACCMODE) = -1

So this actually means that 'invalid argument' refers to O_ACCMODE.

At all kernels I see no changed rights in:
ls -al /dev/fd0
 brw-rw---- 1 root disk 2, 0 May 13 16:43 /dev/fd0

It looks to me that the code in floppy.c is quite old; no changes here.
So the bug is elsewhere in the kernel.

Could someone please explain and repair the magic that is happening here?

Thanks in advance, Wim Osterholt.


----- wim@djo.tudelft.nl -----

             reply	other threads:[~2016-06-10 23:09 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-10 23:02 Wim Osterholt [this message]
2016-06-11 13:15 ` VFS regression ? Re: disfunctional floppy driver in kernels 4.5, 4.6 and 4.7 One Thousand Gnomes
2016-06-12  0:23   ` Wim Osterholt
2016-06-13 12:15 ` Jiri Kosina
2016-06-14 18:43   ` Wim Osterholt
2016-06-15  7:09     ` Jiri Kosina
2016-06-15 11:42       ` Wim Osterholt
2016-06-15 13:20       ` Al Viro
2016-06-15 14:13         ` Jiri Kosina
2016-06-15 22:47           ` Wim Osterholt
2016-06-16  7:53             ` [PATCH] floppy: fix open(O_ACCMODE) for ioctl-only open Jiri Kosina
2016-06-30 11:18               ` [PATCH RESEND] " Jiri Kosina
2016-07-25 18:09                 ` Wim Osterholt
2016-07-25 20:48                 ` Jens Axboe
2021-01-19 15:53                   ` Jiri Kosina
2021-01-21  4:44                     ` Denis Efremov
2021-01-21 10:25                       ` Jiri Kosina
2021-01-21 13:28                         ` [PATCH] floppy: reintroduce O_NDELAY fix kernel test robot
2021-01-21 14:44                         ` [PATCH RESEND] floppy: fix open(O_ACCMODE) for ioctl-only open Jiri Kosina
2021-01-21 15:02                           ` Denis Efremov
2021-01-21 15:05                             ` Jiri Kosina
2021-01-22 11:13                               ` [PATCH] floppy: reintroduce O_NDELAY fix Jiri Kosina
2021-01-26  8:21                                 ` Denis Efremov
2021-01-26  9:31                                   ` Kurt Garloff
2021-01-26  9:59                                     ` Denis Efremov
2021-02-04  9:24                                   ` Jiri Kosina
2021-02-04 10:18                                     ` Denis Efremov
2021-01-21 14:45                         ` [PATCH RESEND] floppy: fix open(O_ACCMODE) for ioctl-only open Denis Efremov
2016-06-15 23:07           ` disfunctional floppy driver in kernels 4.5, 4.6 and 4.7 Wim Osterholt
2016-06-15 23:12             ` Jiri Kosina
2016-06-15 23:13             ` Joe Perches
2016-06-14 19:09   ` Al Viro

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