From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <642eaa23a96e09ed6e0e9b9cfad90944@hamnavoe.com>
To: 9fans@9fans.net
From: Richard Miller <9fans@hamnavoe.com>
Date: Mon, 30 May 2016 11:08:36 +0100
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Subject: Re: [9fans] More about /dev/draw
Topicbox-Message-UUID: 95a1de3a-ead9-11e9-9d60-3106f5b1d025

> I think the videocore
> firmware must have changed from BGR to RGB some time since I last
> looked.  I will look into this.

Yes, someone on the netbsd mailing list noticed (Jan 2015):

> Newer Raspberry Pi firmware has changed the framebuffer from BGR to RGB.
> The method we use to set the pixel order (vcprop set pixel order) does not
> seem to work, nor does querying the pixel order (vcprop get pixel order).
>
> The firmware passes this information to the kernel by adding a
> "bcm2708_fb.fbswap" kernel cmdline arg. 0=BGR, 1=RGB. ...

It turns out that the interface 9pi used for querying framebuffer depth
is also now broken.  Setting framebuffer_depth=N in config.txt used to
work for changing the pixel format, now it doesn't.

Sadly there's been a history of the pi firmware interface quietly changing
behind the scenes.  Making a corresponding quiet change to their linux
kernel seems to be considered sufficient documentation.  Sigh.