[PATCHv2 26/31] drm/omap: Create fbdev emulation only for the first DRM connector

[Tomi Valkeinen]

On 25/03/17 23:22, Daniel Vetter wrote:
> On Fri, Mar 24, 2017 at 11:40:47AM +0200, Tomi Valkeinen wrote:
>> From: Peter Ujfalusi <peter.ujfalusi at ti.com>
>>
>> Add fbdev emulation only for the first DRM connector.
>> When the fbdev emulation was created for all connectors with different
>> resolution, the lower res display would only be able to show part of the
>> framebuffer.
>> By creating the fbdev emulation only for the first connector we can avoid
>> this.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> 
> Why this driver-specific behavior? This is how it works everywhere.
> 
> If this doesn't work in some case, then we need to fix this in the fbdev
> helper. Or have a modparam for that. But definitely not diverging
> behaviour between drivers.

The default behavior often results in a rather unusable fbdev on the
other screen.

For example, a board with a low-res LCD and HDMI. Fbdev is created based
in the LCD resolution, and on HDMI you'll get 1080p resolution with a
tiny fbdev. Or, if fbdev is created based on the HDMI resolution, on the
LCD you'll see a tiny portion of the huge fbdev.

I personally did suggest our folks to just disable the fbdev totally,
but apparently there are still some uses for the fbdev, so this patch
seemed like a simple way to make the behavior a bit nicer.

But I agree that it would be best to have this fully configurable, as
different use cases have different needs. Then again, I'd rather just
disable the fbdev than start spending time on improving it =).

 Tomi

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