I have an AMD ATI 4900 FirePro which perfectly supports the 30-bit mode on Photoshop CS6 with my NEC Spectraview Reference display.
Unfortunately this support turned out to be broken with PhotoshopCC. (Please note that Nvidia cards do support 30-bit mode with P. CC).
I found this bug during my trial period, so I wrote to AMD ATI. They confirmed the bug and after a long investigation and months of waiting finally told me that Adobe has acknowledged the problem and will issue a hotfix.
However...nothing has happened yet and I was wondering if Adobe can speed up this release or hotfix.
I'd love to upgrade to CC but I'm not willing to forgo the 30-bit mode and will need to stay with CS6 until this issue is solved.