After hundreds of Galaxy S6 and S6 Edge owners reported that they phones had, and then lost, the always on "OK Google" voice command of Android, a fix is finally rolling out reports Android Police.
Google acknowledged the issue in early May and has now figured out the problem: Inadvertent compatibility issues. In a product support forum thread, the company says users should make sure their Google Search app is up to date and the issue should be resolved.
Samsung has its own voice command software called S-Voice on its phones and it is affected by the current resolution, says Google:
"Please note that "Ok Google" from any screen will be available, however remaining compatibility issues mean that turning on the feature will limit the availability of S-voice hotwording to only when the screen is off. Users who prefer to avoid this can turn off "Ok Google" from any screen."
This makes sense to me. I've seen it before, in fact with my old Moto X, which had Motorola's own always listening feature available. I couldn't have both Motorola's software and Google Android waiting to hear my commands; I had to choose one or the other.
There was some speculation early on that the original issue stemmed from Samsung's use of its own Exynos chipset in the Galaxy S6 and S6 Edge phones.
I didn't figure that to be the issue, mainly because Samsung has used its own chips in flagship Galaxy phones in the past for certain regions of the world. The "OK Google" listening functionality wasn't a problem for those devices.
Regardless of the issue, if the options to use "OK Google" from any screen on your Galaxy S6 or S6 Edge have gone missing, you should see them now or in the very near future.
Android Police says if you can't wait for any server side changes, try to uninstall the Google Search updates from your device and then re-install them by updating the application which may fix the problem.