On Fri, Aug 17, 2001 at 10:10:07AM -0400, Dave Strauss wrote:
> Ah, much much better. I'm now getting more that 350Kbytes/sec
> (depending on the printer and the test file, of course). Even better,
> the garbage data is no more. I have to think that this means that the
> ECP emulation code still has problems.
So it seems. :-/
There is another problem here. If software ECP was being used, WHY?
The port->modes is meant to indicate what the hardware is capable of.
Currently it's doing just that, technically, but it ought to give an
indication of whether parport_pc will actually _use_ that
capability. :-)
I think that the functions that check whether various ECP modes are
available should be inside a CONFIG_PARPORT_PC_FIFO ifdef.
> Other clues that dma is being used:
>
> dmesg
> [ ... ]
> lp0: using parport0 (interrupt-driven).
THE clue is what parport_pc says when it loads. If it says ', dma
%d', then it knows that it can do DMA with this chipset, and will do
so. (Earlier I said to look for 'using FIFO', but that's wrong, and
means that parport_pc knows that the chipset can do PIO, and will use
it. At least in current kernels; I don't remember if this was
actually the case by 2.4.2-acX.)
So, the next step is: are the software ECP emulation bugs fixed in
newer kernels? There were definitely a few that were squashed since
then, so I think probably so.
Tim.
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This archive was generated by hypermail 2b29 : Fri Aug 17 2001 - 10:27:27 EDT