How to configure linux to output to monitor

Question

I'm currently running a lightweight Debian distro on a development board from Compulab. I have to login to the system via serial port everytime. The system has graphical card and the driver is installed and monitor is detected but the system seems not configured to output via graphical drivers? How do I configure Linux to do that?

root@cm-debian:~# dmesg|grep hdmi
mxc_sdc_fb mxc_sdc_fb.1: register mxc display driver hdmi
mxc_hdmi mxc_hdmi: Detected HDMI controller 0x13:0xa:0xa0:0xc1
mxc_hdmi_soc mxc_hdmi_soc.0: MXC HDMI Audio
asoc: mxc-hdmi-soc <-> imx-hdmi-soc-dai.0 mapping ok
  #1: imx-hdmi-soc

when plugin hdmi cable dmesg shows following output

fbcvt: 1920x1080@50: CVT Name - 2.073M9

cat /etc/inttab

# /etc/inittab: init(8) configuration.
# $Id: inittab,v 1.91 2002/01/25 13:35:21 miquels Exp $

# The default runlevel.
id:2:initdefault:

# Boot-time system configuration/initialization script.
# This is run first except when booting in emergency (-b) mode.
si::sysinit:/etc/init.d/rcS

# What to do in single-user mode.
~~:S:wait:/sbin/sulogin

# /etc/init.d executes the S and K scripts upon change
# of runlevel.
#
# Runlevel 0 is halt.
# Runlevel 1 is single-user.
# Runlevels 2-5 are multi-user.
# Runlevel 6 is reboot.

l0:0:wait:/etc/init.d/rc 0
l1:1:wait:/etc/init.d/rc 1
l2:2:wait:/etc/init.d/rc 2
l3:3:wait:/etc/init.d/rc 3
l4:4:wait:/etc/init.d/rc 4
l5:5:wait:/etc/init.d/rc 5
l6:6:wait:/etc/init.d/rc 6
# Normally not reached, but fallthrough in case of emergency.
z6:6:respawn:/sbin/sulogin

# What to do when CTRL-ALT-DEL is pressed.
ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

# Action on special keypress (ALT-UpArrow).
#kb::kbrequest:/bin/echo "Keyboard Request--edit /etc/inittab to let this work."

# What to do when the power fails/returns.
pf::powerwait:/etc/init.d/powerfail start
pn::powerfailnow:/etc/init.d/powerfail now
po::powerokwait:/etc/init.d/powerfail stop

# /sbin/getty invocations for the runlevels.
#
# The "id" field MUST be the same as the last
# characters of the device (after "tty").
#
# Format:
#  <id>:<runlevels>:<action>:<process>
#
# Note that on most Debian systems tty7 is used by the X Window System,
# so if you want to add more getty's go ahead but skip tty7 if you run X.
#
1:2345:respawn:/sbin/getty 38400 tty1
2:23:respawn:/sbin/getty 38400 tty2
3:23:respawn:/sbin/getty 38400 tty3
4:23:respawn:/sbin/getty 38400 tty4
5:23:respawn:/sbin/getty 38400 tty5
6:23:respawn:/sbin/getty 38400 tty6

# Example how to put a getty on a serial line (for a terminal)
#
#T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
#T1:23:respawn:/sbin/getty -L ttyS1 9600 vt100
T0:23:respawn:/usr/local/bin/getty.sh

# Example how to put a getty on a modem line.
#
#T3:23:respawn:/sbin/mgetty -x0 -s 57600 ttyS3

Solution

The first thing you have to do is confirm whether or not the kernel really has a driver available for the display.

Search online for the card in relation to linux to see if you can find out the name of the driver. If you have a kernel source tree available, you can also look for clues with there:

find src/ -name Kconfig -print -exec grep 'some phrase' '{}' \;

Where 'some phrase' is a manufacturer and/or model number, etc. The Kconfig files contain info used by "make menuconfig" when you manually compile a kernel.

If you think you have a candidate, try loading it with modprobe [name].

If the kernel was compiled specifically for that board, the driver may be built into it -- although if this were the case, you shouldn't be having a problem. If it wasn't, the kernel needs the driver in an initramfs.img. If it isn't there, once the root filesystem is mounted, even if it detects the display and loads the driver (from /lib/modules), I don't think it will do anything with it -- I have not tried this in a while. On that chance, you could look at the output of lsmod to see if a module you think should be the driver is actually loaded.

Comments

[goldilocks]

Debian eh? Post your /etc/inittab, maybe it's not spawning any gettys. What happens when you boot with the HDMI cable plugged in?

[gmc]

@goldilocks i just posted it

[goldilocks]

Ok, I dunno. I'm not so sure that mxc_sdc_fb mxc_sdc_fb.1: register mxc display driver hdmi indicates that the kernel has a driver for the graphics chip. The fb things (that + fbcvt) probably reference the framebuffer device, but that requires a lower level hardware driver.

[gmc]

@goldilocks nothing happens except 'No signal'

[goldilocks]

How did you install?