Could be a fault with the Mother board. Could be a grounding fault. First thing that I would check is continuity on the RS232 port ground pin to the motherboard earth with a multimeter (say one of the black leads from the power supply). It's my first guess that the port has a bad ground connection, and that you are seeing a current flow out of the output signals back through the input signals down to ground via input pull down resistors on the motherboard, or in the chip-set. If you have access to a CRO I would say that it would be worth looking at the serial port wave forms. On Tue, 2008-12-09 at 03:34 +1100, Russell Shaw wrote: > Hi, > > I'm running 2.6.24 on debian/unstable. > > I have an Asus P5E-V-HDMI (Intel G35 chipset) with on-board rs232 serial port. > > http://www.asus.com/products.aspx?l1=3&l2=11&l3=584&l4=0&model=1929&modelmenu=1 > > > With an LED breakout box connected, i get these signals asserted > when doing: cat random.txt > /dev/ttyS0: > > TD faint green > RD flickering red and green > RTS red > DTR red > > When i'm not sending anything i get: > > TD red > RD green > RTS green > CTS red > DSR red > DCD red > DTR red > > > IIRC, RD should not be asserted red or green at all because it > should be an input. > > My other serial cards behave ok. > > I checked the cable between the motherboard and breakout box. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-serial" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
