Linus Torvalds [off-list ref] writes:

On Sat, 25 Oct 2003, Egbert Eich wrote:

quoted

Speaking of XFree86: when I developed the PCI resource stuff in 
XFree86 I was trying to get support from kernel folks to get the 
appropriate user space interfaces into the kernel. When I got 
nowhere I decided to do everything myself. 

There won't be any "user space interfaces". There are perfectly good 
in-kernel interfaces, and anybody who needs them needs to be in kernel 
space. Ie the kernel interfaces are for kernel modules, not for user space 
accesses.

Well almost.    There is still one significant flaw in the kernel space stuff.

The BIOS can specify arbitrary regions as reserved in the E820 map and then
a kernel driver can't use that region itself.  This shows up in corner
cases where the resource on the PCI device is a boolean rather than
a general purpose thing.  Particularly for mtd map drivers to allow
flashing your ROM from linux this is a problem.

This is not required for 2.6.0 but it would be nice to actually be able
to reliably reserve resources in kernel drivers.

Eric


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