Messages in this thread | | | Date | Sat, 9 Jan 1999 14:14:47 -0800 | From | Sang Kang <> | Subject | Re: serial port problem with 2.1.132-2.2.0pre5 |
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On Fri, Jan 08, 1999 at 11:46:42PM -0500, Theodore Y. Ts'o wrote: > 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
Ahh... You are right afterall. i used 16550 instead of 16550A for UART.
Thanks,
Sang Kang
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