[PATCH 09/20] drm fb_helper: use lists for crtcs.

[Sascha Hauer]

On Fri, Feb 03, 2012 at 10:04:27AM +0000, Dave Airlie wrote:
> On Wed, Feb 1, 2012 at 10:38 AM, Sascha Hauer <s.hauer at pengutronix.de> wrote:
> > The fb helper uses fixed size arrays for the associated crtcs.
> > This is an unnecessary limitation, so instead use a list to
> > store the crtcs and allocate them dynamically.
> 
> I need more reasons on why this is a unnecessary limitation, for what?
> 
> Its a lot less cache friendly to use a linked list here for not much gain,

How often do you change modes? This code is run when the user changes
virtual terminals, which is not very performance critical.

> 
> do you want to attach/detach crtcs from fb at runtime?

I am working on a mid layer to connect simple framebuffer devices to
kms and it would be convenient to just add a crtc to a drm device once
it appears. This works fine for connectors and encoders, why not also
for crtcs?

Sascha

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