Disagreement between blueman-manager and hcitool

RandomTroll · 01-11-2023, 09:41 AM

I just started using a bluetooth device for the first time. It's a cheap portable speaker. It powers itself down if it isn't used for a time. When this happens, I turn it on and it pairs automatically - so it says (it speaks) - but doesn't emit the sound mplayer sends. mplayer thinks it's playing. I have to run blueman-manager. hcitool doesn't even see the device, even on a scan. How can they have different information?

pan64 · 01-12-2023, 02:04 AM

auto power off is detected and device will be removed from the list. But player probably still trying to use it, it did not recognize the change. When you switch it on again the player still wants to use the "old", remembered device, and not the new one. It also cannot detect if it is the same one. Probably because some id changed in the background somewhere.

computersavvy · 01-12-2023, 08:28 PM

As noted above, and as you stated, when unused the speaker does an auto power down.
In that situation you should shut down mplayer before you start the speaker back up so that when mplayer is restarted it sees the active device for output.

RandomTroll · 01-13-2023, 06:04 AM

Quote:

Originally Posted by pan64

auto power off is detected and device will be removed from the list. But player probably still trying to use it, it did not recognize the change. When you switch it on again the player still wants to use the "old", remembered device, and not the new one. It also cannot detect if it is the same one. Probably because some id changed in the background somewhere.

Quote:

Originally Posted by computersavvy

As noted above, and as you stated, when unused the speaker does an auto power down.
In that situation you should shut down mplayer before you start the speaker back up so that when mplayer is restarted it sees the active device for output.

Both of your answers assume wrongly. mplayer isn't running, hasn't been for a while. I turn the speaker on, it says it pairs. Then I start mplayer anew.

Code:

hcitool scan

doesn't even find the speaker. blueman-manager does: that's the first question: how can they have different opinions of what's present?

The second question is why mplayer can think it's playing but no sound comes out of the speaker.

pan64 · 01-13-2023, 06:22 AM

it is slightly different. mplayer does not communicate with the speaker, but some library (pulseaudio?). And that library (whatever is it) did not recognize the change, so mplayer will use it (even if the real device is missing) with the old config. As far as I see this is a very low level problem (if hcitool cannot detect it)
probably this helps a bit: https://9to5answer.com/hcitool-scan-...uetooth-device

RandomTroll · 01-13-2023, 11:39 PM

Quote:

Originally Posted by pan64

this is a very low level problem (if hcitool cannot detect it)

One would think that hcitool is closer to the hardware than blueman-manager.