There is no problem under the battery mode, and because the system halts that
makes unable to collect any dmesg.

$ DRI_PRIME=1 glxgears -info                                                    
Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
GL_RENDERER   = Gallium 0.4 on AMD HAINAN (DRM 2.50.0 /
4.14.0-041400rc5-generic, LLVM 4.0.0)
GL_VERSION    = 3.0 Mesa 17.0.7
GL_VENDOR     = X.Org
...

$ DRI_PRIME=0 glxgears -info
Running synchronized to the vertical refresh.  The framerate should be
approximately the same as the monitor refresh rate.
GL_RENDERER   = Mesa DRI Intel(R) Kabylake GT1.5
GL_VERSION    = 3.0 Mesa 17.0.7
GL_VENDOR     = Intel Open Source Technology Center
...