On 07/03/13 11:53, Russell King wrote:
On Wed, Jul 03, 2013 at 06:48:41PM +0900, Inki Dae wrote:
That's not whether we can write device driver or not. dtsi is common spot in other subsystems. Do you think the cardX node is meaningful to other subsystems?
Yes, because fbdev could also use it to solve the same problem which we're having with DRM.
Inki,
I do not understand why you keep referring to the SoC dtsi. Im my example, I said that it is made up and joined from both SoC dtsi and board dts.
So, of course, lcd controller nodes and dcon are part of dove.dtsi because they are physically available on every Dove SoC.
Also, the connection from lcd0 to the external HDMI encoder node is in the board dts because you can happily build a Dove SoC board with a different HDMI encoder or with no encoder at all.
The video-card super node is not in any way specific to DRM and describes a virtual graphics card comprising both SoC and board components (on a per-board basis). You can have both DRM or fbdev use that virtual video card node to register your subsystem drivers required to provide video output.
I agree to what Sascha said, the decision to put one or two virtual graphics card in the device tree depending on the use case is sketchy. You can have one card/two card on the same board, so at this point device tree is not describing HW but use case.
But honestly, I see no way around it and it is the only way to allow to even have the decision for one or two cards at all. There is no way for auto-probing the users intention...
Sebastian