On 9/16/2014 5:37 PM, Jason Kridner wrote: > > Just going along to state the obvious... > > eMMC and HDMI will be equally interesting tests and more practically > useful for more capes.
I'll try and work up a patch set for HDMI, but it won't be until tomorrow. > It will only be a matter of time before someone damages a board by: > A) setting an HDMI pin to a output without disabling the HDMI The worst that can happen with HDMI is a bus fight (driving an HDMI pin without first configuring the BBB side as an input). The HDMI framer does not drive any signals back to the AM335x (other than I2C), so it won't cause problems. If you start playing with pinmux values you could easily see wonky video, but that's not a "break the hardware" kind of problem. > B) driving an eMMC pin into conflict without putting the eMMC in reset This is much more likely, and while it might not be easy to destroy the hardware, it is probably pretty easy to corrupt the eMMC. It might be worth requiring loading an alternate device-tree to disable the eMMC, which can make sure it stays in reset. > I don't think there is a simple way for the current pinmux helper to > check for these conditions, but it wouldn't hurt if any config-pin > sort of utility would check the state of those hardware control bits > before helping someone screw things up. :-) Agreed! > Any way you can imagine a way to keep the current uEnv.txt lines to > disable both of those working without breaking compatibility? Maybe, there's some groundwork to do first. For instance I still don't know what happens if you leave the HDMI enabled, but take all the pins out from under it via the pinmux. I'll keep this in mind and see what I can come up with... -- Charles Steinkuehler [email protected] -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
