fbcon on one of multiple displays

[Eric Nelson]

Hi Alex,

On 12/4/23 07:40, Alex Deucher wrote:
> On Mon, Dec 4, 2023 at 8:52 AM Eric Nelson <eric at nelint.com> wrote:
>>
>> Thanks Javier,
>>
>> On 12/4/23 03:11, Javier Martinez Canillas wrote:
>>> Eric Nelson <eric at nelint.com> writes:
>>>
>>> Hello Eric,
>>>
>>>> Hi all,
>>>>
>>>> Is there a way to configure a framebuffer console on a specific display
>>>> on a machine with multiple displays?
>>>>
>>>
>>> Have you looked at https://www.kernel.org/doc/Documentation/fb/fbcon.txt ?
>>>
>>> There is a sysfb interface to bind / unbind fbdev devices to fbcon's VT
>>> (/sys/class/vtconsole/vtcon1/bind) and also kernel command line parameter
>>> to choose which fbdev driver is mapped to which VT console (fbcon=map:n).
>>>
>>
>> I have seen this, but it's not clear how we can use this. In our case,
>> we have a single driver for two displays.
>>
>> I hope to get a device on my desk this week to test it out.
> 
> Are you referring to two devices that just both happen to use the same
> driver, or multiple displays driving by a single device?  For the
> latter, drm drivers at least only expose a single "display" via the
> fbcon emulation.
> 
> Alex

A little of both.

There are multiple displays through a single driver, but the fbcon 
emulation is only creating a single framebuffer device.

What we're aiming for is pretty simple. We just want to get a splash 
screen (fb logo) to display on one of them and haven't found the right path.