Messages in this thread | | | From | jbradford@dial ... | Subject | Re: 2.5.x and 8250 UART problems | Date | Sat, 5 Oct 2002 21:01:46 +0100 (BST) |
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> > > > I've noticed that 8250 UART based serial port performance is poorer in > > > > 2.5.x than 2.4.x and 2.2.x, on a couple of my machines. > > > > > > > > The 486 SX-20 with 4 MB RAM, running 2.2.21 reliably achieves about 650 > > > > BPS download from another machine, with the port runnnig at 9600 bps. > > > > With 2.5.40, many characters are lost at 9600, making, e.g. a ZModem > > > > transfer retry for almost every block. > > > > > > Have you tried 'hdparm -u'? > > > > Hmmm, I can do, but I thought it was a Bad Thing (tm) for ISA based > > controllers? I could be wrong... > > Shouldn't it be fixed, it should work normally anyway.
Not sure, without interupt unmasking, I would expect excessive disk activity to potentially cause data loss, but there isn't excessive disk activity going on anyway.
If you look at:
http://www.uwsg.iu.edu/hypermail/linux/kernel/0207.3/0373.html
though, you'll see why I was asking for clarification before trying 'hdparm -u', because the laptop in question has a broken floppy drive, so if I corrupt the root filesystem, I've got to take it apart, and put the hard disk in another machine to re-install. Not a five minute job, by any means!
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