want a way to tell that the dump will fail when devices don't support polled I/O
Some devices that end up being used as part of a dump device do not support polled I/O. Unfortunately, when this happens we have little way of knowing that this is the case until we try and fail to dump. It'd be useful to have dump creation fail, maybe have it fail to activate (due to a part change), or something else.
Updated by Garrett D'Amore about 5 years ago
I'd actually recommend having the DDI decorate devices with a "dump-capable" or "can-polled" property or some such, and then have dumpadm check that property. The DDI can do this by the existence of the dump(9e) entry point. Device drivers that need to enable this conditionally can update the property as needed.