[igt-dev] [PATCH v6 05/13] fb: Fix ARGB8888 color depth

[Maxime Ripard]

On Wed, Sep 05, 2018 at 01:14:34PM +0300, Ville Syrjälä wrote:
> > In the same format list:
> >   - RGB565 has a depth of 16
> >   - XRGB8888 has a depth of 24
> >   - XRGB2101010 has a depth of 30
> >   - ARGB8888 has a depth of 32
> > 
> > Which seems to indicate that the list indeed meant that the color
> > depth is about the color, and that ARGB8888 is wrong.
> 
> None of those other things have alpha, so they are still
> consistent with the depth==32 definition for ARGB888.

"24 bits almost always uses 8 bits of each of R, G, B. As of 2018
24-bit color depth is used by virtually every computer and phone
display and the vast majority of image storage formats. Almost all
cases where there are 32 bits per pixel mean that 24 are used for the
color, and the remaining 8 are the alpha channel or unused."

There's 32bpp, but the depth is 24 bits.

But maybe the X11 legacy says otherwise, I don't know. What's your
suggestion then? adding yet another field?

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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