LinuxQuestions.org - Bluetooth mouse low battery problem

I wasn't aware that you'd get low battery warning on the slave BT device. Just at some point the mouse stops working because the battery is too low. But not doubting you. I guess I'd research what driver was being used for that mouse and seeing if there were ways to disable settings like the equivalent of ACPI for that device, if something like that exists. I'd see if the system log contained events about this and, worst case; find the source for the driver, edit it and add debug or change it so that it didn't do that.

In looking a bit more the Bluetooth HID Profile specification talks about the requirements for support for low power link modes. The slave device can negotiate the characteristics of this mode. If the slaves do not request this mode, the host can also request/designate use of this mode. I find it hard to believe that two different mouse HID devices are misbehaving against the spec, unless they're both the same manufacturer or same interface chip. More likely is that the driver in Saucy may have a flaw where it ignores the low power mode sniff requests from the slaves and makes incorrect assumptions.

For starters, I'd try and diagnose just what is happening in Linux, what events you can find and whether or not there are options which you can configure for your Bluetooth driver. Obviously way better than trying to determine if either side's driver is adhering to the spec properly.