Can anybody help this man?
p.
attached mail follows:
Hi,
I'm currently developing an external hardware that receives data via ECP
from a Compaq Armada 300 notebook. I don't know for sure whether the
parallel port is handled by the i82371 or the SMSC-Super-IO, but guessing
from the transfer rates (below 500k/s) it's the SMSC.
Now the problem: With 2.4.10, I got around 350kbyte/s with ECP, the
low-pulses of the strobe signal were at around 500ns. Now with 2.4.19-pre10,
I get only about 250kbyte/s, the low duration increased to about 750ns. The
250kbyte/s are too slow for my (realtime) device, so I have a problem.
Switching back to the old kernel solves this issue...
Do you know what has changed between 2.4.10 and 2.4.19 that can cause this
slowdown? I've searched the parport_pc-code for timing related stuff, but
found nothing useful. Can it be caused by some changed "tuning" of the
PCI-ISA-bridge?
The detection output when loading parport_pc with specified io, irq and dma
looks like this:
parport0: PC-style at 0x378 (0x778), irq 7<7>0x378: FIFO is 16 bytes
0x378: writeIntrThreshold is 15
0x378: readIntrThreshold is 15
0x378: PWord is 8 bits
0x378: Interrupts are ISA-Pulses
0x378: ECP port cfgA=0x10 cfgB=0x00
0x378: ECP settings irq=<none or set by other means> dma=<none or set by
other means>
, dma 3 [PCSPP,TRISTATE,COMPAT,EPP,ECP,DMA]
Thank you for any hint in tracking this problem...
--
Georg Acher, acher@in.tum.de
http://www.in.tum.de/~acher/
"Oh no, not again !" The bowl of petunias
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