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soc/cores/video: fix framebuffer color output 

An earlier patch fixed the swapped red and blue channels on the HDMI
PHYs. This exposed the fact that the framebuffer readout was swapped
too.

The framebuffer readout is fixed by this patch to match the r5g6b5 and
a8b8g8r8 color format definitions documented in the Linux kernel's
simplefb driver and used by LiteX:
https://www.kernel.org/doc/Documentation/devicetree/bindings/display/simple-framebuffer.txt

This has been tested using 16 bit SDRAM in both supported color formats.

Additionally the green color used by the video terminal is swapped. It
now matches the color used by LiteX on Ubuntu's terminal, from which it
was probably originally sourced.
This commit is contained in:
Thomas Watson 2022-09-30 19:15:56 -05:00
parent 3836e8a36c
commit d27d6fca62
1 changed files with 5 additions and 5 deletions
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10
litex/soc/cores/video.py
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@ -611,7 +611,7 @@ class VideoTerminal(Module):
If(bit, If(bit,
Case(term_rdport.dat_r[font_width:], { Case(term_rdport.dat_r[font_width:], {
0: [Cat(source.r, source.g, source.b).eq(0xffffff)], 0: [Cat(source.r, source.g, source.b).eq(0xffffff)],
1: [Cat(source.r, source.g, source.b).eq(0x34e289)], 1: [Cat(source.r, source.g, source.b).eq(0x89e234)],
}) })
).Else( ).Else(
Cat(source.r, source.g, source.b).eq(0x000000), Cat(source.r, source.g, source.b).eq(0x000000),
@ -680,15 +680,15 @@ class VideoFrameBuffer(Module, AutoCSR):
] ]
if (depth == 32): if (depth == 32):
self.comb += [ self.comb += [
source.r.eq(video_pipe_source.data[16:24]), source.r.eq(video_pipe_source.data[ 0: 8]),
source.g.eq(video_pipe_source.data[ 8:16]), source.g.eq(video_pipe_source.data[ 8:16]),
source.b.eq(video_pipe_source.data[ 0: 8]), source.b.eq(video_pipe_source.data[16:24]),
] ]
else: # depth == 16 else: # depth == 16
self.comb += [ self.comb += [
source.r.eq(Cat(Signal(3, reset = 0), video_pipe_source.data[ 0: 5])), source.r.eq(Cat(Signal(3, reset = 0), video_pipe_source.data[11:16])),
source.g.eq(Cat(Signal(2, reset = 0), video_pipe_source.data[ 5:11])), source.g.eq(Cat(Signal(2, reset = 0), video_pipe_source.data[ 5:11])),
source.b.eq(Cat(Signal(3, reset = 0), video_pipe_source.data[11:16])), source.b.eq(Cat(Signal(3, reset = 0), video_pipe_source.data[ 0: 5])),
] ]
# Underflow. # Underflow.