Re: [PATCH 1/3] ide: add "ignore_hpa" module parameter

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

> Please note that no fancy sysfs support was needed to prevent the problem:
> both stacks (ide & libata) support HDIO_DRIVE_TASK ioctl which can be used
> to execute commands needed to retrieve/change HPA setting.

Wrong. You need sysfs support because you may not be able to retrieve the
HPA settings after the drive has removed them. You also need a trigger of
some form because the block layer needs to see the volume resized and it
doesn't snoop the innards of the ATA command structure.
 
> Moreover the (much needed) work from Tejun doesn't help a tiny bit in case
> of people migrating their *working* setups from IDE to libata (at least
> in distro upgrade case this could have been handled by distro installer but
> see above) and hitting the compatibility issue mentioned in bug #13365.

Fedora handled it with clear documentation at the time. I'm not sure how
other distros handled it back then but given the patch was written by
Ubuntu folk I suspect they knew about it too 8)