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Saravana Kannan authored
Consider this example where -> means LHS device is a consumer of RHS device and indentation represents "child of" of the previous device. Device A -> Device C Device B -> Device A Device C Without this commit: 1. Device A is added. 2. Device A is added to waiting for supplier list (Device C) 3. Device B is added 4. Device B is linked as a consumer to Device A 5. Device A doesn't probe because it's waiting for Device C to be added. 6. Device B doesn't probe because Device A hasn't probed. 7. Device C will never be added because it's parent hasn't probed. So, Device A, B and C will be in a probe/add deadlock. This commit detects this scenario and stops trying to create a device link between Device A and Device C since doing so would create the following cycle: Device A -> Devic C -(parent)-> Device B -> Device A. With this commit: 1. Device A is added. 3. Device B is added 4. Device B is linked as a consumer to Device A 5. Device A probes. 6. Device B probes because Device A has probed. 7. Device C is added and probed. Signed-off-by:
Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20200610011934.49795-3-saravanak@google.comSigned-off-by:
Rob Herring <robh@kernel.org>
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