Re: [9fans] Small Plan 9 Platforms

[Steve Simon <steve@quintile.net>]

Vncserv must do something similar, maybe that is worth looking at.
I went down a similar route but am planning to just address the display
as a different type of device, rather than as a plan9 display.

Your progress is very impressive, my project stalled - I must get back to it.

-Steve



On 15 Aug 2015, at 03:49, Brian L. Stuart <blstuart@bellsouth.net> wrote:

>> I have tried to email BLS but fear I am being spam filtered... you there?
>
> I did get one message from you, and replied earlier today.  Hopefully
> it got through.
>
> A little more update on recent pi playing.  I've been working on a
> little toy the last few days, namely one of those small SPI driven
> LCD panels:
>
> http://www.adafruit.com/products/2441
>
> As of this evening, I've gotten it sort of running alongside the
> HDMI display showing the upper left corner.  Here are a few
> pics of it in operation:
>
> The Pi with the display connected to a keyboard and mouse:
>
> http://cs.drexel.edu/~bls96/9pitft1-s.jpg
>
> and a couple of pics of the display showing acme running:
>
> http://cs.drexel.edu/~bls96/9pitft2-s.jpg
> http://cs.drexel.edu/~bls96/9pitft3-s.jpg
>
> It's a long way from being usable though.  The fundamental issue
> is that there appears to be a very deeply embedded assumption
> that a screen must be memory mapped.  I tried hooking into
> the hwdraw() routine in screen.c, but it seems that not every
> change to the screen memory space gets reflected in a call
> to hwdraw().  For the pics, I've got a version that periodically
> copies the whole of the appropriate area of the Memimage
> to the LCD panel over the SPI port.  Obviously, that's too slow
> and too resource-hungry to be practical.  Hopefully, I'm missing
> something and there's an elegant way to graft a non-memory
> mapped display into the devdraw/memdraw/screen infrastructure.
>
> BLS
>