I did a kernel update on my Linux machine today (to 2.6.35-25-generic-pae) and I find that my FTDI cable suddenly won't auto-reset the arduino clone I have on a breadboard. In fact it's worse - it just seems to hold pin 1 low constantly.
I only managed to do an upload after having disconnected the RTS wire from pin 1, which means going back to manually pressing reset before an upload.
I was puzzling as to why this suddenly was the case... and thought about the recent kernel update. I tried booting back into 2.6.35-24-generic-pae and everything works as it used to.
I assume something's changed in a driver somewhere...
So this isn't really a question, more just to say what I've noticed in case anyone else is puzzled about strange new behaviour However, if anyone can shed more light on this, feel free to comment...
Which seems to confirm my theory that the driver has changed. Comment seems to imply that this is a deliberate change in the Linux code - therefore the IDE presumably needs a bit of a change to set RTS low when the port is opened.
I just updated to 2.6.35-25 myself, but it is working fine here on an official Duemilanove. It auto-resets on upload as normal. This is on Ubuntu 10.10 x86_64
I'm kind of glad I didn't try to fix it by upgrading my kernel because it looks like it's broken on the latest one as well. Apparently they randomly change the FTDI drivers' behavior for some reason. Do you remember what kernel you had before where the FTDI cable WAS working as expected? Since my netbook is basically my Arduino terminal, I'd just as soon use that kernel.
My temporary fix is to cut the pads as per manual reset/upload then solder a 100nF cap across. This makes it a lot less fiddly than trying to time the reset just right, but I have to unplug-then replug in the board every time I want to make a fresh upload - go figure!
Coincidentally, there seems to be no problem with the mega, also I've tried using a little FTDI module from RS components, connecting just the serial lines, and the RTS# line via a 100nF cap. That works perfectly (which is why it took me so long to discover there was a problem). I don't know if it's relevant but this development board of my own doesn't share the +5V with the USB module.
dmesg|grep ftdi_sio
ftdi_sio 5-2:1.0: FTDI USB Serial Device converter detected
uname -a
Linux mark-laptop 2.6.35-26-generic #46-Ubuntu SMP Sun Jan 30 06:59:07 UTC 2011 x86_64 GNU/Linux