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* [9front] rpi4 RGB24 vs BGR24, glitches and golang status
@ 2021-02-27  8:49 p.kosyh
  2021-02-27 11:54 ` hiro
  2021-02-27 16:54 ` ori
  0 siblings, 2 replies; 5+ messages in thread
From: p.kosyh @ 2021-02-27  8:49 UTC (permalink / raw)
  To: 9front

Hello!  I finally bought rpi4 4Gb specially for 9front. It seems,
that default bpp of framebuffer is 16.  I changed it to 24 (via
cmdline.txt and config.txt) and found, that rendering is much faster!
(May be due removing overheads in 16->24 conversions?)

But on rpi4 r and b channels are swapped.  So, i changed BGR24 to
RGB24 in bcm/screen.c and now it works fine!  I am not sure, if this
patch will work on rpi3/2/1, so i just wrote this message if it will useful
for someone.

The next problem.  Sometimes i see strange artefacts on screen.  If i
run acme with lot of text i see pale character places (like vertical
bars) in other parts of the screen.  /dev/screen does not contain
those data.  I checked hdmi cable and monitor with Linux.  No problem.
Can it be something with alpha blending calculations or something like
this?  Is there an experiment i could do?  Btw i remember that i saw
such artefacts in 9front running in amd64 qemu on AMD (non Intel)
host.

Golang does not support plan9/arm64 target.  Because arm64 is
9front only :) Is anyone working on it or it is too hard to implement?




^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-02-27 20:20 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-27  8:49 [9front] rpi4 RGB24 vs BGR24, glitches and golang status p.kosyh
2021-02-27 11:54 ` hiro
2021-02-27 14:54   ` p.kosyh
2021-02-27 16:56     ` hiro
2021-02-27 16:54 ` ori

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