[Gta04-owner] Linux 3.2-rc2 on GTA04

NeilBrown neilb at suse.de
Thu Nov 24 23:20:36 CET 2011


On Thu, 24 Nov 2011 23:04:13 +0100 Johannes Schauer <j.schauer at email.de>
wrote:

> Hi,
> 
> On Fri, Nov 25, 2011 at 08:29:48AM +1100, NeilBrown wrote:
> > On Thu, 24 Nov 2011 21:57:04 +0100 "Dr. H. Nikolaus Schaller"
> > <hns at goldelico.com> wrote:
> > > > The gpio line can be controlled from /sys/class/gpio/gpio57
> > > > 
> > > > cd /sys/class/gpio/gpio57
> > > > echo 1 > value
> > > > 
> > > > however I suspect you will find that '1' is already the value.
> 
> no, the value I find there is 0
> 
> > > > I didn't change any of this code from the code David had, except
> > > > that I replaced the base kernel:-) So presumably there is some
> > > > change in common code that is messing things up.
> 
> but the backlight works fine before xorg comes up - i can see the
> penguin.
> 
> > > Are you sure that the backlight really turns off? Or does the
> > > framebuffer turn completely black? In that case you see some light
> > > glowing. If you remove the battery, there should be a noticeable
> > > change.
> > 
> > The original report said that shining a bright torch the display made the
> > image just visible, so it wasn't blank, just no backlight.
> > Very strange.
> 
> yes, it is the backlight. here is a photo of the display with my
> flashlight shining on it:
> 
> http://mister-muffin.de/p/VDGp.jpg
> 
> you can faintly see the e17 language selection menu with the USA flag in
> the center of the photo.
> 
> after doing:
> 
> 	echo 1 > /sys/class/gpio/gpio57/value
> 
> or:
> 
> 	echo 1 > /sys/devices/virtual/gpio/gpio57/value
> 
> the display will turn on.
> 
> after some time e17 will turn off the display. this works properly and
> the values in */gpio/gpio57/value will correctly change to 0 but when
> tapping the display (touchscreen works) the values will still remain
> zero and backlight will not come back until one does echo 1 > ...
> again.

Something strange here.  Glad that the GPIO pin is clearly working, but
cannot imagine why it isn't being turned on.

How do "gta04_enable_lcd" and "gta04_disable_lcd" dmesg messages align with
the other events.
In particular, when the display is dark and you tap the display, do you get
the message "gta04_enable_lcd" even though it doesn't turn on the backlight,
or do you not get the message at all?

(Also - glad to know the touch screen and display and all is basically
working - that is all in upstream code now.  David's kernel had lots of
display related patches that I don't need because Linus has them!).

Thanks,
NeilBrown

> 
> the exact same image with xorg7.6+e17 is working fine with davids 3.1
> kernel.
> 
> cheers josch
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