Re: [PATCH] fix HDIO_GETGEO ioctl for linux

[Szakacsits Szabolcs]

On Thu, 17 Nov 2005, Andres Salomon wrote:
> On Thu, 2005-11-17 at 13:03 +0100, Szakacsits Szabolcs wrote:
> > On Wen, 16 Nov 2005, Andres Salomon wrote:
> > 
> > > I ran into a problem when running parted on Ubuntu Breezy with an sx8
> > > device; it would SIGFPE upon startup.  The culprit, it turns out, is the
> > > HDIO_GETGEO ioctl; 
> > 
> > This is very interesting. HDIO_GETGEO is completely useless for
> > partitioning and it was supposed to be removed over a year ago.
> 
> It looks like hdparm still uses it, too.

It probably reads the disk physical geometry for some reason but for
partitioning, one needs the BIOS legacy geometry used for booting on 
such obscure systems that's still in use by hundreds of millions people.
HDIO_GETGEO returns the disk physical geometry, not the one needed.

> > If for some reason its wrong values end up to be used then that could
> > explain why people are still corrupting their partition tables.
> 
> There's a comment in the code that suggests moving to EDD.  However, in
> linux, that requires loading edd.ko (which is a module in debian
> kernels, and is completely disabled in ubuntu kernels).  

Sooner or later they will catch up, other distros include it already for 
a long time. 

        Szaka

> Anyone know of another way to access EDD services?  Once edd.ko is
> actually loaded, we end up w/ /sys/firmware/edd in 2.6.