On 6 July 2012 23:54, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote: >> Would Linux block my ability to manually probe these i/o ports? > > Not beyond reserving the region which you've said you've covered. > > What you may want to try is making sure Linux doesn't program the DMA > controller (in case its doing something which disables the port in poking > at it). > > Beyond that I guess ask the manufacturer for info. Thank you. It turned out that I needed to configure the Southbridge. I managed to get a complete datasheet and I have set all the correct registers in the Southbridge to enable COM9 at port 0x010 with irq 9 (default values). Either the BIOS or Linux changed it from the default values. I set the correct values in my serial port init_ function and autoconfig detects the UART now. # dmesg <snip> Serial: 8250/16550 driver, 5 ports, IRQ sharing disabled serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A serial8250: ttyS2 at I/O 0x3e8 (irq = 4) is a 16550A serial8250: ttyS3 at I/O 0x2e8 (irq = 3) is a 16550A Vortex init of South Bridge for COM9 serial8250.11: ttyS4 at I/O 0x10 (irq = 9) is a 16550A </snip> I still have a problem though, I can't seem to use the device. e.g. # echo hello > /dev/ttyS4 sh: write error: Input/output error # cat /dev/ttyS4 sh: write error: Input/output error # picocom -b 115200 /dev/ttyS4 FATAL: failed to add device /dev/ttyS4: Filedes is not a tty # cat .config <snip> # # Serial drivers # CONFIG_SERIAL_8250=y CONFIG_SERIAL_8250_CONSOLE=y CONFIG_FIX_EARLYCON_MEM=y CONFIG_SERIAL_8250_NR_UARTS=5 CONFIG_SERIAL_8250_RUNTIME_UARTS=5 CONFIG_SERIAL_8250_EXTENDED=y CONFIG_SERIAL_8250_MANY_PORTS=y CONFIG_SERIAL_8250_VORTEX=y </snip> # cat /proc/tty/drivers /dev/tty /dev/tty 5 0 system:/dev/tty /dev/console /dev/console 5 1 system:console /dev/ptmx /dev/ptmx 5 2 system /dev/vc/0 /dev/vc/0 4 0 system:vtmaster serial /dev/ttyS 4 64-68 serial pty_slave /dev/pts 136 0-1048575 pty:slave pty_master /dev/ptm 128 0-1048575 pty:master unknown /dev/tty 4 1-63 console There only appears to only be 4 ttySx drivers in use. # cat /proc/tty/driver/serial serinfo:1.0 driver revision: 0: uart:16550A port:000003F8 irq:4 tx:19983 rx:548 RTS|DTR|RI 1: uart:16550A port:000002F8 irq:3 tx:0 rx:0 2: uart:16550A port:000003E8 irq:10 tx:0 rx:0 3: uart:16550A port:000002E8 irq:11 tx:7 rx:0 4: uart:16550A port:00000010 irq:9 tx:0 rx:0 Aras -- 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
