Paul Fulghum wrote:
Lee Howard wrote:
And in repeat tests it is quite evident that IDE disk activity is,
indeed, at least part of the problem. As IDE disk activity increases
an increased amount of data coming in on the serial port goes missing.
Lee, you mentioned 2.2.x kernels did not
Mark Lord wrote:
The "fix" could be to have the serial IRQ handler never unmask
interrupts,
but that's a bit unsociable to others. The IDE stuff really needs to not
do so much during the actual IRQ handler.
Ingo's RT patches would probably fix all of this.
I did a Fedora 7 installation and
Ray Lee wrote:
On 7/27/07, Lee Howard <[EMAIL PROTECTED]> wrote:
Curiously, the session at 38400 bps that skipped 858 bytes... coincided,
not just in sequence but also in precice timing within the session, with
a small but noticeable disk load that I caused by grepping through a
h
Maciej W. Rozycki wrote:
On Fri, 27 Jul 2007, Lee Howard wrote:
Okay, so let's say we've got a loop around a blocking read on the modem file
descriptor...
for (;;) {
read some data from modem
process data from modem
if (end-of-data detected) break;
}
Are you sugge
Alan Cox wrote:
Curiously, the session at 38400 bps that skipped 858 bytes... coincided,
not just in sequence but also in precice timing within the session, with
a small but noticeable disk load that I caused by grepping through a
hundred session logs. (I can't reproduce it easily, though, be
Paul Fulghum wrote:
So this seems to be a latency issue reading the receive
FIFO in the ISR. The current rx FIFO trigger level
should be 8 bytes (UART_FCR_R_TRIG_10) which gives the
ISR 694usec to get the data at 115200bps.
IIRC, in 2.2.X kernels this defaulted to 4 bytes
(TRIG_01) which gave a
Paul Fulghum wrote:
Tilman Schmidt wrote:
Could this be related?
http://lkml.org/lkml/2007/7/18/245
Quote:
"I've recently found (using 2.6.21.4) that configuring a serial ports
(ST16654) which use the 8250 driver using setserial results in the
UART's FIFOs being disabled (unless you specify
Tilman Schmidt wrote:
Lee Howard schrieb:
So, does this explain why I wouldn't have a problem at 115200 bps with
kernel 2.2.5 but why I do with 2.6.5 and 2.6.18? Both hardware and
software flow control work fine with 2.2.5 (meaning I don't see any
error message and I don'
Maciej W. Rozycki wrote:
The TTY line discipline driver could do that based on the amount of
received data present in its buffer. And it should if asked to (a brief
look at drivers/char/n_tty.c reveals it does; obviously there may be a bug
somewhere though). So could e.g. the SLIP and PPP li
Alan Cox wrote:
As the flow control is driven by software on most 16x50 chips (there are
a couple of exceptions) if we fail to empty the fifo fast enough then any
flow control will be asserted too late to save the day.
If you stop the application and do the following
cat /dev/ttywhatev
Maciej W. Rozycki wrote:
On Thu, 26 Jul 2007, Lee Howard wrote:
If the application were to use TIOCM_RTS how would it know when to apply it or
not? Is there some approach that the application could take to manage flow
control on the serial port? What about software flow control? Does
Alan Cox wrote:
The manufacturer is using a scope to look for RTS and they're not seeing
it, either. I just use my eyes to look at the LED, but I can see the
CTS, DTR, DCD, RD, and TD lights blink, flicker, or dim... (and TD, RD,
and CTS tend to go on and off rather quickly).
And you h
Alan Cox wrote:
Serial: 8250/16550 driver $Revision: 1.90 $ 8 ports, IRQ sharing enabled
ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
It's a Shuttle HOT-661 motherboard (VIA Apollo Pro Plus mainboard
chipset). Both FreeBSD and Linux identify the serial chi
Uwe Kleine-König wrote:
Hello,
This is evidenced in hardware flow control by a little LED labeled "RTS"
that is on the external modem. This LED lights up when pin 7 of the DB9
serial connection is given +12Vdc current (signalling "RTS" is on - that
the host can accept data). The LED goe
Robert Hancock wrote:
Lee Howard wrote:
Hello.
I have fax modems that will, in their proper behavior with certain
features, send up to 64 kilobytes of data to the host DTE all at
once. (So, the fax modem handles an incoming fax and periodically
will send between 256 bytes and 64
Hello.
I have fax modems that will, in their proper behavior with certain
features, send up to 64 kilobytes of data to the host DTE all at once.
(So, the fax modem handles an incoming fax and periodically will send
between 256 bytes and 64 kilobytes of data in bursts.)
When the DCE-DTE (mod
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