Bluetooth adapter is not getting detected in newer kernels
by Shubh64337 from LinuxQuestions.org on (#5489W)
Hi, I have installed many distributions and in all of them with kernel versions 5.x, bluetooth adapter doesn't get detected in the dmesg log. There is no hci0 device detection in dmesg. I have a dual boot setup with windows 10. In windows, bluetooth works fine. However, if I install a distribution with 4.19.x kernel or install ubuntu's 4.19.x kernel on a distro and boot from that kernel, my hci0 bluetooth adapter gets detected and works fine. My bluetooth adapter is realtek rtl8723d. Also, the adapter gets detected even in the newer kernels if it is in a virtual machine, but not in dual boot.
Moreover, once I am in the older kernel in linux and bluetooth is working fine, if I boot into newer kernel, obviously, bluetooth doesn't work in that, but now, even if I reboot into older kernel, bluetooth stops working there too! Then I have to boot at least once into windows to make bluetooth work in the 4.19.x kernels. It seems like the newer kernel sort of leaves the adapter in a useless state which is restored only by Windows.
Can anybody please tell me why bluetooth adapter is not getting detected in newer kernels and how can I make it work?
Moreover, once I am in the older kernel in linux and bluetooth is working fine, if I boot into newer kernel, obviously, bluetooth doesn't work in that, but now, even if I reboot into older kernel, bluetooth stops working there too! Then I have to boot at least once into windows to make bluetooth work in the 4.19.x kernels. It seems like the newer kernel sort of leaves the adapter in a useless state which is restored only by Windows.
Can anybody please tell me why bluetooth adapter is not getting detected in newer kernels and how can I make it work?