On 05/24/18 11:18, Mark Brown wrote:

On Thu, May 24, 2018 at 12:50:17PM -0500, Rob Herring wrote:

quoted

Subsystems or drivers may opt-in to this behavior by calling
driver_deferred_probe_check_init_done() instead of just returning
-EPROBE_DEFER. They may use additional information from DT or kernel's
config to decide whether to continue to defer probe or not.

Should userspace have some involvement in this decision?  It knows if
it's got any intention of loading modules for example.  Kernel config
checks might be good enough, though it's going to be a pain to work out
if the relevant driver is built as a module for example.

A parallel issue is that loading an overlay could provide the resource
that will allow the deferred probe to complete.  (That is, once we
finish implementing the run time overlays feature.)

-Frank