I'm not sure how general this is, hence sent to LKML and IIO. Some of the devices we have can produce interrupts indicating that everything has gone horribly wrong. Sometimes this is also embedded in the main data stream. The best examples are all the 'wonderful' ways the ad2s1210 resolver can go wrong. None of these would be expected to be part of normal operating conditions. So, the question is - do we want these to go through our main events stream? They are weird and wonderful and often don't align well with our existing event codes. Loss of data error for example (a wire came out). Others could possibly be made to fit but that would loose some of the semantics. Loss of tracking could be a rate of change threshold event, but it really is meant to tell you the data could be garbage. So three options come to mind: 1) Have a magic set of event codes for device class specific fault events and push through our main event path. For reference of non IIO types - that is an anon file descriptor obtained by an ioctl on the devices chrdev. Events are a simple timestamp / eventcode pair. 2) Add another anon file that you get via an ioctl as a separate event reporting channel. We then define a big list of error codes without aiming for any real structure. Drivers would then need to document what they can throw out (preferably under sysfs?) 3) Consider these out of band (from the out of band event data) and look at other options for reporting them. Is there anything general out there for reporting hardware failures that would be appropriate? Sometime these conditions are the sort of thing that should cause a siren to go off. They might be sensor failure.... or they might mean you have a runaway train heading for a station... (p.s. I hope no one is using the current driver for trains, though that might explain British trains...) Thanks, Jonathan -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
