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SubjectRe: [BUG] pnpbios breaks floppy support
Quoting Robert Hancock <>:

> Philippe De Muyter wrote:
>> On Sun, Feb 01, 2009 at 01:08:33AM -0600, Robert Hancock wrote:
>>> Philippe De Muyter wrote:
>>>> Hello linux experts,
>>>> Today I tried to upgrade a PC's kernel from 2.6.11 to 2.6.22, and
>>>> I saw some strange messages when booting :
>>>> Floppy drive(s): fd0 is 1.44M
>>>> floppy0: Floppy io-port 0x03f2 in use
>>>> Previously, I had :
>>>> Floppy drive(s): fd0 is 1.44M
>>>> FDC 0 is a post-1991 82077
>>>> Needless to say, my floppy hardware works perfectly, and my floppy
>>>> was usable with the old kernel, while the floppy is now inaccessible
>>>> with the new kernel. Even /dev/fd0 does not exist anymore.
>>>> Searching for a cause to that problem, I saw the following messages
>>>> before the floppy probe in the new kernel :
>>>> PnPBIOS: Scanning system for PnP BIOS support...
>>>> PnPBIOS: Found PnP BIOS installation structure at 0xc00fd5e0
>>>> PnPBIOS: PnP BIOS version 1.0, entry 0xf0000:0x5ba3, dseg 0xf0000
>>>> PnPBIOS: 17 nodes reported by PnP BIOS; 17 recorded by driver
>>>> [...]
>>>> pnp: 00:07: ioport range 0x3f0-0x3f1 has been reserved
>>>> pnp: 00:07: ioport range 0x3f3-0x3f3 has been reserved
>>>> [...]
>>>> Searching the web and the outdated pnp kernel documentation, I
>>>> finally found an option to add to my kernel parameters line :
>>>> pnpbios=off
>>>> Now my floppy works again, but I am not really satisfied.
>>>> What do I loose with the 'pnpbios=off' option ?
>>>> Isn't there a smoother option to allow pnpbios but avoiding to reserve
>>>> floppy's io-ports ?
>>>> Should I modify rather /drivers/block/floppy.c or /drivers/pnp/*.c
>>>> to make pnpbios and floppy driver coexist peacefully ? And is there
>>>> an example of such modifications for other standard peripherals ?
>>> Presumably the problem is that your BIOS marks the IO ports used by
>>> the floppy controller as reserved which prevents the floppy driver
>>> from binding to them. (2.6.11 probably was before we even processed
>>> PnP reserved regions.)
>>> I think we now have handling for the case where the reservations
>>> overlap PCI devices, but I think it's the first I've heard of them
>>> overlapping the floppy IO ports..
>> I should have added that, when started with pnpbios enabled, I have
>> found the following in /sys/devices/pnp0/ :
>> $ cat 00:03/id
>> PNP0700
>> $ cat 00:03/resources state = active
>> io 0x3f4-0x3f5
>> io 0x3f2-0x3f2
>> irq 6
>> dma 2
>> $ cat 00:03/options
>> port 0x3f4-0x3f4, align 0x0, size 0x2, 16-bit address decoding
>> port 0x3f2-0x3f2, align 0x0, size 0x1, 16-bit address decoding
>> irq 6 High-Edge
>> dma 2 8-bit compatible
>> AFAIK, PNP0700 is the pnp id for the standard floppy disk,
>> and the resources and options files describe the expected io-ports
>> of the floppy disk, so this does not seem to be an error in the bios.
> There's likely another resource with id of PNP0C01 or PNP0C02
> (Motherboard resources) which contains that same IO port range.

Yes, could you post the same information for 00:07 so we can start to narrow
this down? Also having "cat /proc/ioports" couldn't hurt.


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