[PATCH 0/4] fb support for 8bpp bitmaps

Keith Packard keithp at keithp.com
Mon Jan 13 18:00:35 PST 2014

Here's a fun sequence of patches. What it does is make fb support
bitmaps (depth 1 pixmaps) that are stored in 8 bits per pixel. Why
would you want to do this, you ask? Well, Glamor wants to use GL for
all rendering, and GL has no support for 1bpp surfaces. Making fb
support bitmaps in 8bpp means we'll have "native" format support in GL
for the same pixmaps which means we can map them instead of copying

The tricky parts here involve stippling and copy plane operations,
those are handled by creating a fetching function that reads 32 
bytes from the source and converts that into 32 bits.

I've run the piglit-wrapped X test suite with these changes and it now
matches the old code

A new function, fbSetBitmap8bpp, can be called by drivers to select
this new mode.

I can easily imagine changing that function into something which took
the actual bpp instead of only offering a boolean, in case we want to
also support 32bpp bitmaps.

Just rename these two macros to avoid potential conflicts:
 [PATCH 1/4] fb: Rename READ/WRITE macros to FB_READ/FB_WRITE

Makes sure we don't try to fetch data beyond depth when doing XY GetImage:
 [PATCH 2/4] fb: Clear invalid plane mask bits in GetImage

The fb changes:
 [PATCH 3/4] fb: Add support for 8-bpp pixmaps

And the way I tested this:
 [PATCH 4/4] ephyr: Add -bitmap8 flag to specify 8 bpp for bitmaps


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