Date: Sun, 3 May 1998 03:16:56 +1000 From: Bruce Evans <bde@zeta.org.au> To: dillon@backplane.com, freebsd-bugs@FreeBSD.ORG Subject: Re: i386/5398 Message-ID: <199805021716.DAA15845@godzilla.zeta.org.au>
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> :actually, this is probably due to a device that isn't with-in the spec'd > :rs-232 speeds... I have the same problem with the ricochet on my > :notebook... I can't run faster than 19.2kbps because the ricochet runs > :about 5% over the 19.2kbps clock (I get about 2050int/sec at 19.2kbps).. > : > :try running the speeds lower... > > Ahh.... nonsense. Unless the serial port is out of sync more then 1/2 > bit time every 10 bits, the 16x oversampling done by the 16xxx has no > problem dealing with this issue. Also since the problem is demonstratably It would need to be out of sync by -1/2 bit time every single bit for input to appear to arrive much faster (about twice as fast). > cpu out of suds? This is a pentium pro 200. More likely, there is a > serious interrupt disablement latency somewhere in the kernel. More likely, there something outside the kernel is disabling interrupts. Even more likely, the graphics card is using a significant fraction of the bus bandwidth, so ISA interrupt handlers run much slower than normal. It takes about a 10x slowdown to cause silo overflows with the default fifo trigger level (4 times more when you reduce the level to 8). Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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