On 02.05.24 09:18, Pere Garcia wrote:
Hi Jon, SystemReady IR owner here at ATG. May I ask, what would be the purpose of DTB provided by the OS? The primary function (not only one) of DTB from a SystemReady perspective is for the Platform (fw) advertise to the OS what's in there, there are other secondary functions and some vendors use DTB to store FW-only information or proprietary data structures that do not break the interoperability to OSes. Is such OS DTB containing platform information, or is this DTB containing data useful for the OS or meaningful to be originated from the OS ? can you please elaborate a bit?
Thanks in advance, Pere
Device-trees are a mixture of hardware description and operating instructions for the kernel (e.g. baudrate of the UART, driver or host operating mode of a USB port).
Device-tree overlays may be needed for optional hardware (e.g. Raspberry hats).
Linux device-trees evolve over time. Full board support cannot be expected with an outdated device-tree provided by firmware. Furthermore both backward and forward incompatibilities occur from time to time.
Using the device-tree matching the booted kernel typically provides the best user experience.
Best regards
Heinrich