role of crtcs in modesetting interfaces and possible abstraction away from userspace

[Aaron Plattner]

On 09/08/2014 11:37 PM, Keith Packard wrote:
> With atomic mode setting in the kernel, I think you're probably right in
> proposing to eliminate explicit CRTC allocation from that. I do think
> you'll want to indicate the number of available CRTCs in the display
> engine, and the number of CRTCs each monitor consumes. Do you know if
> there are some of these monitors that can display lower resolution modes
> with only a single CRTC? Or is the hardware so separate that you end up
> always using multiple CRTCs to drive them?

The one I tried definitely can; indeed it has to because the VBIOS 
doesn't know how to set up MST and drives the port in DP 1.1 mode.  I'm 
sure someone will build a monitor that only turns on half of the display 
if you do that, but I'd be kind of surprised if someone made one that 
just doesn't work if you use a DP 1.1-only GPU.

-- 
Aaron