Re: user space writel() etc. in 2.2.2

Alan Cox (alan@lxorguk.ukuu.org.uk)
Fri, 5 Mar 1999 17:51:17 +0000 (GMT)

> Alpha + sparse memory + mmap'ed frame buffer + mmap'ed control
> registers.
>
> I am not that familiar with the sparse mem but I doubt mmap() has a
> kludge to get around it (I found out the hard way why readl/writel is
> needed when porting the AceNIC driver to run an Avanti).

The Alpha functions sometimes use a kernel jump table. Im sure thats really
going to work well from user space. The moment you go digging into devices
directly from user space you lose portability.

Alan

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/