Mini2440 LCD Standby Problem

Hey guys,

We're just a couple of guys who bought ourselfes a hand of mini2440 boards
with X35 LCDs. We are using buildroot at university and crosscompiled the
2.6.38rc6 kernel (thanks by the way).

Now our major problem is, that we are redirecting the default console to
our X35 displays and have a bootup logo plus a blinking cursor. Though we
don't have any HID devices, we cannot "login" - but can successfully write
on the display (echo... tty1) or show pictures using fbv. But after 7-8
minutes the displays go into a state of standby - their backlights are
turned of. I can reactivate the display (echo 1 > backlight) but there is
no more output on it - even after writing new output.
I think though there is no "interaction" with the default console it just
powers off (management?) to save energy. Any ideas how to get rid of that?

i think davef has already mentioned it in here - dunno if he has figured it
out until now...

Cheers

You can play with the "setterm" command and it's parameters (e.g. -blank,
-powersave and so on), to get rid of the screen blank.

Thanks for your fast answer Jürgen. It looks like setterm isn't included,
neither in buildroot nor in busybox.

Okay, by googeling with setterm and busybox I found this:
http://www.friendlyarm.net/forum/topic/1133#6695

Will check that out.

You can also first echo 0 to shut off the backlight, and then directly echo
1 to power it on, then it will stay on for 10 min more. 

How do you btw use fbv to view pictures without a keyboard, is there any
way to exit fbv with some echo command?

Well the problem was not directly the backlight - With the 2.6.38 kernel i
was able to de/activate it but no "output" was appearing on the screen.
Like on normale Linux distributions where your screen goes into power
saving. Only after I connected a USB Keyboard and pressed a button the
output came back...

I'm directly connected via RS232 for debugging purposes (with FTDI USB to
seriell connector), but it should also be possible to use SSH (dropbear is
already running).

If you do not want to use a real console on your device, you can disable
the graphical console in the kernel config. Then you will get a plain
framebuffer you can run your graphical application on. Without the
graphical console there is nobody switching off the screen anymore. But in
this case you will need a patch like this one (to activate it the first
time):

Subject: Enable display even without graphics console

If no graphics console is enabled the LCD gets not activated otherwise.

---
 drivers/video/s3c2410fb.c |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-2.6.38/drivers/video/s3c2410fb.c
===================================================================
--- linux-2.6.38.orig/drivers/video/s3c2410fb.c
+++ linux-2.6.38/drivers/video/s3c2410fb.c
@@ -982,6 +982,9 @@ static int __devinit s3c24xxfb_probe(str
                dev_err(&pdev->dev, "failed to add debug attribute\n");
        }
 #endif
+#ifndef CONFIG_FRAMEBUFFER_CONSOLE
+       s3c2410fb_set_par(fbinfo);
+#endif
        pr_info("fb%d: %s frame buffer device\n",
                fbinfo->node, fbinfo->fix.id);

Hey Jürgen,

Thanks for your fast answer. First, do you think it's possible to drop you
some lines via mail if we have major problems? We'r currently studying at
HS Augsburg :)

I just made major steps forward, so my 2.6.39 Kernel is working with the
patches, supplied in this forum (which are also part of your pengu
package). I'm currently showing rrdtool graphs on the diplays but still
have that blinking cursor from a console menu.

I tried to find your patch above - but i think those lines are more related
to 2.6.38 than to 2.6.39 anymore... Maybe you can do a quick check? Thanks
:)

MFG

Gr3yh0und: You can use our mailing list. Refer
http://www.friendlyarm.net/forum/topic/2737