* Ryan Mallon [off-list ref] wrote:

On 17/06/11 19:30, Ingo Molnar wrote:

quoted

* Petr Tesarik[off-list ref]  wrote:

quoted

This patch series enhances /dev/mem, so that read and write is
possible at any address. The patchset includes actual
implementation for x86.

This series lacks a description of why this is desired.

My strong opinion is that it's not desired at all: /dev/mem never
worked beyond 4G addresses so by today it has become largely obsolete
and is on the way out really.

I'm aware of these current /dev/mem uses:

 - Xorg maps below 4G non-RAM addresses and the video BIOS

 - It used to have some debugging role but these days kexec and kgdb
   has largely taken over that role - partly due to the 4G limit.

 - there's some really horrible out-of-tree drivers that do mmap()s
   via /dev/mem, those should be fixed if they want to move beyond
   4G: their char device should be mmap()able.

There are drivers where this makes sense. For example an FPGA 
device with a proprietary register layout on the memory bus can be 
done this way. [...]

So you want us to help vendors screw users with insane, proprietary, 
user-space drivers with sekrit binary blobs?

Wow.

Thanks,

	Ingo