nanogui: Thread: Nano-X display problem: swapped pixel columns w/ Kyocera QVGA LCD, also touchscreen mapping issue

Apologies in advance for posting... I am looking for the source of the
issue and a solution myself, but my project is high priority enough that
I wanted to make a query here first, in parallel.
 
I have an ADS Graphics Client Plus with a Kyocera KCS057QV1AD-G23
passive color QVGA 3-bit LCD (w/ the SA configured to drive it in frame
modulation mode, yielding a more reasonable 12 bits, 4-4-4, though
subject to the time constant).
 
I'm running the correct kernel with SA register settings appropriate for
the display. On boot, Tux shows up correctly.
 
When I run any Nano-X application, however, I see even and odd pixel
columns swapped. To be precise: column 0 and 1 are swapped, 2 and 3 are
swapped, and so forth. The screen image appears to be the proper size,
however (QVGA, 320 x 240).
 
Nano-X is compiled with FRAMEBUFFER=Y.
 
Has any one seen behavior like this in any other situations?
 
-----
 
Also, since moving from the original ADS GC+ reference LCD (a VGA
display) to the Kyocera, I see that the touchscreen is still reporting
values appropriate for VGA... does there exist calibration code
anywhere? (In fact, whose issue would that be, Linux or Nano-X?)
 
Many thanks in advance for any feedback...
 
-Marc Cygnus
 

On Tue, 28 Jan 2003 10:28:25 -0600
"Marc W. Cygnus" ####@####.#### wrote:

> Apologies in advance for posting... I am looking for the source of the
> issue and a solution myself, but my project is high priority enough that
> I wanted to make a query here first, in parallel.
>  
> I have an ADS Graphics Client Plus with a Kyocera KCS057QV1AD-G23
> passive color QVGA 3-bit LCD (w/ the SA configured to drive it in frame
> modulation mode, yielding a more reasonable 12 bits, 4-4-4, though
> subject to the time constant).
>  
> I'm running the correct kernel with SA register settings appropriate for
> the display. On boot, Tux shows up correctly.
>  
> When I run any Nano-X application, however, I see even and odd pixel
> columns swapped. To be precise: column 0 and 1 are swapped, 2 and 3 are
> swapped, and so forth. The screen image appears to be the proper size,
> however (QVGA, 320 x 240).
>  
> Nano-X is compiled with FRAMEBUFFER=Y.
>  
> Has any one seen behavior like this in any other situations?

I've seeen a very similar situation on a greyscale LCD.

The LCD I use is 4 bppp and has a 4 bit data bus.  For some reason, it
expects to get pixels in this order: 1,0,3,2  instead of 0,1,2,3.
I'm not sure why, but it sounds like the same problem you're having.

I had to modify the fb4lin.c driver to do a nibble-flip.

I've attached the driver.  Perhaps you could apply similar modifications
to whichever of the color drivers you're using.

Maybe nibble-flipping could be a generic feature in a future release of
microwindows.  It seems like a couple of people have needed nibble-flipping
drivers recently.

Hope this helps.

Dave Muse
####@####.####


>  
> -----
>  
> Also, since moving from the original ADS GC+ reference LCD (a VGA
> display) to the Kyocera, I see that the touchscreen is still reporting
> values appropriate for VGA... does there exist calibration code
> anywhere? (In fact, whose issue would that be, Linux or Nano-X?)
>  
> Many thanks in advance for any feedback...
>  
> -Marc Cygnus
>  
> 

On Tue, 28 Jan 2003 10:28:25 -0600
"Marc W. Cygnus" ####@####.#### wrote:

> When I run any Nano-X application, however, I see even and odd pixel
> columns swapped. To be precise: column 0 and 1 are swapped, 2 and 3
> are swapped, and so forth. The screen image appears to be the proper
> size, however (QVGA, 320 x 240).

Hmm... it seems that your framebuffer memory is
arranged differently than your processor (I don't want to say
different endian here, because I'm not sure if the bit order is
reversed or not).  That happens occasionally. The Helio had a similar
problem, so we used drivers/fblin4rev.c to fix it. You will
just need to extend that same concept out for your 12 bit system.

Regards,
Jordan