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Too slow on high numbered serial ports!

i got a multi-port serial card (MSC) connected to a mother board via PC/104 ISA bus. there are eight serial ports on the MSC, but any of them can only be associated with ttyS2 or ttyS3 (i did not tried ttyS0,1 for they are already used by the mother board itself). if i associated (via setserial command) any of them to ttyS4+, a very _long delay_ will be detected on both direction of RX and TX.

those ports all shared a common irq (not occupied by other devices) but with different io base address. i doubt there is a kernel configuration problem, but i just have no a clue.

the version of linux kernel is 2.2.x (yes, it's too old, but we used it with some other brand of multi-port serial boards w/o problem).

any clue? thanks in advance.

--
steven woody (id: narke)

John McFarland: Hey, what are you guys doing?
Alex: Get the fuck out and don't come back! Some heavy shit's going down! 

	- Elephant (2003)
Reply to
Steven Woody
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I think there is in the kernel .config a line to set the number of extra ports you want to use.

Anjo

Reply to
abakwa

ISA

RX

can you recall what is the option? i checked the dmesg output and found a line of something like "linux serial driver version xxx with MANY_PORTS and SHARED_IRQ support". did you mean that additonal to MANY_PORTS, the kernel still has extra option to let you specify exactly how many ports you reall need?

Reply to
narke

ISA

RX

Reply to
abakwa

abakwa wrote: Steven just remembered that some time ago we installed on an advantech UNO box PC computer with 4 ports that port 3 and 4 where behaving erratic and very slow. The fault was in the irq and the io address of the ports which must be different then in the doc was mentioned. After correction with setserial it worked fine. Greetings Anjo

ISA

RX

Reply to
abakwa

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