Hi,

I'm not a newbie, but I am trying to understand the semantics of deferred 
probing.

My question is generic, but for an example:

Let's say I have a platform driver "A" for a device "a", that requires device 
"b" (controlled by driver "B") to be operational first. Both A &B can be built 
as part of kernel, or as modules independently.  As far as I could tell, there 
is no way to specify the ORDER in which the drivers' probe routines should be 
called. I took a look at modprobe / depmod, but it seems to be of relevance for 
modules only that are loaded from user space. My questions:

1) Is there a way to specify that "Kernel should call A's probe routine only 
after B's probe routine"?

2) How I currently do this: In A's probe routine, I currently check if the 
device "b" is available. If not, I return -EPROBE_DEFER. This mostly works ok. 
However, I'm curious about the case where the driver B is not built as part of 
the kernel but A is. After getting an _EPROB_DEFER from a B's probe routine, 
when will the kernel try again? And for how long would it keep on trying? I 
verified that if I load the driver B manually from user space, the A's probe 
routine does not get called (if it gets called now - it would have returned 
success!).

Thanks,

Rajat

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