Messages in this thread | | | From | Andries.Brouwer@cwi ... | Date | Thu, 23 May 2002 00:46:23 +0200 (MEST) | Subject | Re: [PATCH] 2.5.17 /dev/port |
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> Anybody: if you've ever used /dev/ports, holler _now_.
Holler.
In my eyes /dev/port is a rather unimportant corner of the kernel. Removing it does not streamline anything, we hear that it saves 454 bytes. A worthy goal, but..
Today a few things use /dev/port. Some low level mouse, keyboard and console utilities. kbdrate. hwclock.
Is it needed? Hardly - most uses can be replaced by inb() and outb(). But I am not sure why that would be better. And I seem to recall that hwclock on some flavours of Alpha really needed the /dev/port way. But I may be mistaken.
I have also seen systems that used /dev/port as the implementation of inb() and and outb(): outb(int p, char v) { lseek(fd,p,0); write(fd,&v,1); } That way one could access keyboard, sound, rtc etc while the underlying hardware was rather different from i86.
A further advantage of having /dev/port is that it allows one to set keyboard or mouse or whatever properties from anything that is able to access a file. But outb() or ioctl() probably require something close to a C environment. Probably this is what Alan is saying.
It is rather unimportant, but there are a few uses, and removing it does not really have any positive effect. Quickly the 454 bytes won will be lost again to the new ioctls, and to the filesystem that Al develops to set the border colour of the monitor screen and become a bleeding edge developer too.
Andries
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