nanogui: Nano-X display problem: swapped pixel columns w/ Kyocera QVGA LCD, also touchscreen mapping issue
Subject:
Re: [nanogui] Nano-X display problem: swapped pixel columns w/ Kyocera QVGA LCD, also touchscreen mapping issue
From:
David Muse ####@####.####
Date:
28 Jan 2003 16:53:52 -0000
Message-Id: <20030128114618.79ca7147.dmuse@4accesscommunications.com>
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
>
>
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