On Wed, Dec 14, 2016 at 04:40:15PM +0800, John Hsu wrote:

On 12/13/2016 2:12 PM, Ben Zhang wrote:

...

+static SOC_ENUM_SINGLE_DECL( + nau8825_class_g_enum, SND_SOC_NOPM, 0, nau8825_class_g_src); +

The register SND_SOC_NOPM can't use at the enum put and get function in the older kernel. Ex. kernel 3.14. The driver has to modify the DAPM in the platform with older kernel.

Older kernels are not relevant upstream. If you need to backport that should be handled separately.