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

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
	eben@raspberrypi.org, igt-dev@lists.freedesktop.org,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [igt-dev] [PATCH v6 05/13] fb: Fix ARGB8888 color depth
Date: Wed, 5 Sep 2018 16:37:26 +0300	[thread overview]
Message-ID: <20180905133726.GR5565@intel.com> (raw)
In-Reply-To: <20180905131903.ucuftgtcq4hzze2s@flea>

On Wed, Sep 05, 2018 at 03:19:03PM +0200, Maxime Ripard wrote:
> 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?

Just leave it as is?

-- 
Ville Syrjälä
Intel
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