Messages in this thread | | | Date | Fri, 8 Jan 1999 23:46:42 -0500 | From | "Theodore Y. Ts'o" <> | Subject | Re: serial port problem with 2.1.132-2.2.0pre5 |
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Date: Thu, 7 Jan 1999 04:09:29 -0800 From: Sang Kang <kernel@mocha.sarang.net>
The issue is that, when I first issued that command (at+...?) using the mouse's middle button, not all characters were copiled to the serial port but rather forgotten some characters, only displaying "at+". when I typed the entire AT command, it worked fine, but when the input is too fast it seems to loose the characters. Changing the baud rate lower didn't help.
This one's easy. You have one of the buggy uart's which failed to deal with the new IRQ autodetection (which changed as part of code simplification and an attempt to deal with other buggy uarts....)
Check with setserial; you probably have an rc.serial file which is trying to do IRQ autodetection, and the autodetection is failing, leaving your IRQ for the port set to zero. Hmm... perhaps I should patch the serial driver to set the irq back to its original value if the autodetect fails, since that's more likely to work.
The right answer is to hard code the IRQ in your rc.serial script, and simply declare the irq to be a specific value. Unfortunately, IRQ detection on the ISA bus is devilishly hard to do right, and it can be failing for any number of reasons. It doesn't help that 100 different manufacturers have tried to do clones of the National Semiconductor UART, but many of them don't do competent jobs. So writing generic code which works for all of them is not particalarly easy.
- Ted
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