On 10/10/2017 19:12, Ian Lepore wrote: > i2c -s is not a thing that's done routinely in a production system or > normal system operations... it's something a person does manually when > trying to configure or debug a system. In that situation, there is > more harm in being told there are no working devices on the bus when in > fact everything is fine, than there is some some hypothetical device > doing some hypothetical "bad thing" in response to a read command. In > all my years of working with i2c stuff I've never seen a device doing > anything more harmful than hanging the bus, requiring a reset (and even > causing that requires worse behavior than an unexpected read). On the > other hand, I've seen a lot of people frustrated that i2c -s on freebsd > says there are no devices, while the equivelent command on linux shows > that everything is fine.
Okay. However, I will just mention that in the past I used to own a system where scanning the bus would make a slave that controlled CPU frequency to change it to some garbage. The system "just" crashed, but theoretically the damage could have been worse. Also, I own a system right now where scanning the bus results in something like what you mentioned, but a little bit worse, the hanging bus that can be brought back only by a power cycle (not even a warm reset). -- Andriy Gapon _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
