Re: RFC: Compact Flash True IDE Mode Driver

[Kumar Gala <galak@kernel.crashing.org>]

On Feb 13, 2006, at 10:53 AM, Bartlomiej Zolnierkiewicz wrote:

> On 2/13/06, Kumar Gala <galak@kernel.crashing.org> wrote:
>
>>>> +static void cfide_outsl(unsigned long port, void *addr, u32 count)
>>>> +{
>>>> +       panic("outsl unsupported");
>>>> +}
>>>
>>> This will panic as soon as somebody tries to enable 32-bit I/O
>>> using hdparm.  Please add ide_hwif_t.no_io_32bit flag and teach
>>> ide-disk.c:ide_disk_setup() about it (separate patch).
>>
>> I'm not sure I follow this, can you expand.
>
> Do "hdparm -c 2 /dev/hdx" first and then read/write to the device
> and you should see it. :)
>
> We need to make "hdparm -c 2" (and "hdparm -c 3") unsupported
> (see how "io_32bit" setting is handled in ide_add_generic_settings()
> and how it can be read-only or read-write setting depending on the
> value of drive->no_io_32bit).
>
> To do this we need to set drive->no_io_32bit to 1 (see how
> ide_disk_setup() handles it).  Unfortunately 32-bit I/O capability
> is based on capabilities of both host and device so we have to
> add new flag hwif->no_io_32bit to indicate that host doesn't
> support 32-bit I/O.

This all make sense, should I check for hwif->no_io_32bit in  
idedisk_setup() and set drive->no_io_32bit to 1 if hwif->no_io_32bit  
is 1 or do this the test in ide_add_generic_settings()?

- kumar