Problem:

When the user swipes down from the upper right edge of the screen to display Control Panel, they find that the audio switch icon is greyed out and does not work, and a dialog box is displayed.

Cause:

The audio channel may have been being used in other scenarios, resulting in the audio switch icon being greyed out.

Solution:

1. Confirm what the audio channel is being used for based on the following, stop the current task, and try again.
   • If a dialog box is displayed indicating that it is unable to switch devices as audio is being used for wired projection, disable the projection and try again.
   • If a dialog box is displayed indicating that it is unable to switch devices as audio is being used for Wireless Projection, disable Wireless Projection and try again.
   • If a dialog box is displayed indicating that it is unable to switch devices as audio is being used for Multi-Screen Collaboration, disable Multi-Screen Collaboration and try again.
   • If a dialog box is displayed indicating that it is unable to switch devices as audio is being used by Huawei HiCar, disconnect the automotive head unit that is connected to the phone and try again.
   • If a dialog box is displayed indicating that it is unable to switch devices as audio is being used for a call, end the call and try again.
   • If a dialog box is displayed indicating that it is unable to switch devices as audio is being used for the radio, turn off the radio and try again.
2. If the issue persists after you perform the preceding operations, restart your phone and try again.