On 30/09/14 11:03, Dr. H. Nikolaus Schaller wrote:
The same kernel/bootargs should work on a BeagleBoard.
No, they shouldn't. Bootargs are device specific.
Yes, they are - but having them device specific only makes trouble... The problem is if the boot loader is in flash memory updating the kernel (on a SD card) to do something special means reflashing.
Our concept is to try to keep the boot-loader stable and have no assumptions about the kernel. So that we can even swap SD cards between different devices.
But the same kernel binary should work on both devices, of course.
The best long-term solution is IMHO to get rid of all bootargs and rely on the device-specific DT which is more or less equivalent of a big bootarg string.
Well, where does the DT blob come from? It must be device specific. You can either get the bootargs from the same place where the DT blob is, or you can use "bootargs" property in the DT blob itself to define device specific bootargs.
Well, it could be possible that the boot loader fetches device-specific boot-args from SD card but that would duplicate the mechanism that is already used for loading device specific device trees.
Anyways this seems to work.
Perhaps, but it may fail at any time. There's no reason for the kernel to allow bad bootargs.
The patch wasn't accepted by Tony, as he wants a DT based solution, and I have not been able to come up with a way to implement such a solution. And as there's been no DSI based boards in the mainline, it has been on low priority.
It works!!! Many thanks!
If the Pyra is finished we will have a DSI based board in the mainline.
So we will help to get it there :)
Ok. I actually have a work-in-progress branch that uses syscon to do the DSI muxing, which is probably acceptable for Tony. But it's still quite ugly, and I haven't had time to finalize it.
Tomi