We recently had an emergency issue with a client system and had issues with the iDRAC7 remote control features. We put iDRAC cards in all of our servers for exactly this scenario where there is an unknown issue and we might need to power cycle the system.
We were able to log into the iDRAC7 web console with no issues. However, on the summary screen it was not showing status for the power supplies. Also, if I tried to browse the disk status, it was indicating the no disks or controllers could be seen.
Fortunately, the fix was pretty easy. Just restart the iDRAC card. To do this, on the Summary screen, in the Quick Launch Tasks, click Reset iDRAC as shown below. This does not reset the configuration of the iDRAC, it just restarts the card.