On Wed, 29 Jan 2003, Tim Waugh wrote:
> On Wed, Jan 29, 2003 at 08:56:16PM +0000, Joe Lang wrote:
> > Is there a way to query the kernel (or some other system resource)
> > to determine the I/O ports used by a parallel port adaptor?
> > You know, the base/data, the status, and the control I/O ports.
> > I do understand that the status and control ports are offset from the base,
> > so if I can get the base, that would be enough.
> The first question to ask it whether you need to know those numbers at
> all. The kernel provides an interface for accessing those ports
> without needing to know things like base addresses (the ppdev driver).
How does one use ppdev...like /dev/ports?
What if there are 2 or more parallel adaptors?
> Also, you can use a library like libieee1284 to get a nicer
> programming interface to it.
> > If I look at the output from the dmesg command I see info like:
> > parport0: PC-style at 0x378 [SPP,PS2]
> > How does the parport driver determine the 0x378 value displayed above?
> The kernel figures this out by guessing, largely.
You are kidding...right?
In the old days we would look at segment 0x40 (the bios data area)
when a protected mode processor was in real mode to determine such information.
How much other guessing is done in Linux?
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This archive was generated by hypermail 2b29 : Wed Jan 29 2003 - 18:29:05 EST