Hi, * Frank Rowand <frowand.list@xxxxxxxxx> [160412 13:15]: > Hi Tony, > > I agree with the need for some way of handling the incomplete > hardware issue. I like the idea of having a uniform method for > all nodes. > > I am stumbling over what the status property is supposed to convey > and what the "fail-hw-incomplete" is meant to convey. > > The status property is meant to convey the current state of the > node. > > "fail-hw-incomplete" is meant to describe the node implementation, > saying that some portions of hardware that the driver expects to > be present do not exist. If I understood your explanation at ELC > correctly, an examples of this could be that a uart cell is not > routed to transmit and receive data pins or the interrupt line > from the cell is not routed to an interrupt controller. So the > node is not useful, but it makes sense to be able to power manage > the node, turning off power so that it is not wasting power. Yes cases like that are common. > It seems to me that the info that needs to be conveyed is a > description of the hardware, stating: > - some portions or features of the node are not present and/or > are not usable > - power management of the node is possible > > Status of "fail-sss" is meant to indicate an error was detected in > the device, and that the error might (or might not) be repairable. > > So the difference I see is state vs hardware description. OK thanks for the clarification. I don't see why "fail-hw-incomplete" could not be set dynamically during the probe in some cases based on the SoC revision detection for example. So from that point of view using status with the "fail-sss" logic would make more sense. > I would prefer to come up with a new boolean property (with a > standard name that any node binding could choose to implement) > that says something like "only power management is available for > this node, do not attempt to use any other feature of the node". Heh that's going to be a long property name :) How about unusable-incomplete-idle-only :) > With that change, the bulk of your patch looks good, with > minor changes: > > __of_device_is_available() would not need to change. > > __of_device_is_incomplete() would change to check the new > boolean property. (And I would suggest renaming it to > something that conveys it is ok to power manage the > device, but do not do anything else to the device.) I'm fine with property too, but the runtime probe fail state changes worry me a bit with that one. I think Rob also preferred to use the status though while we chatted at ELC? Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
