Re: [PATCH] IDE disks show invalid geometries in /proc/ide/hd*/geometry

[Mark Bellon <mbellon@mvista.com>]

Jan Engelhardt wrote:

> > Simple: do not use BIOS values.
> > [ Yes, there should be some warning from kernel. ]
> >    
>
> On that matter, I get a warning from LILO wrt cyls and stuff:
>
> 07:47 spectre:~ # cat /proc/ide/hda/geometry 
> physical     16383/16/63
> logical      65535/16/63
> 07:58 spectre:~ # lilo
> Warning: Kernel & BIOS return differing head/sector geometries for device 0x80
>    Kernel: 65535 cylinders, 16 heads, 63 sectors
>      BIOS: 1023 cylinders, 255 heads, 63 sectors
> Added linux *
> 07:59 spectre:~ # fdisk -l
>
> Disk /dev/hda: 40.9 GB, 40982151168 bytes
> 255 heads, 63 sectors/track, 4982 cylinders
>
>
> All of these numbers are virtual, since CHS is not really used anymore, as 
> we know. But, which of these fake CHS values (16383/16/63 | 65535/16/63 | 
> 1023/255/63) is the right one? 255/63/4982 is another matter, since it 
> [almost] matches the actual size of the disk while the other three are just 
> "for the bios".
>  
This is exactly the case that my patch was attempting to fix (and 
apparently didn't get quite right).

Certain drive returns cause strange numbers to slip through often when 
LBA 28 is involved.

mark

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