#4296 closed defect (notsugar)
SugarExt volume control set volume to 0
| Reported by: | dsd | Owned by: | erikos |
|---|---|---|---|
| Priority: | Unspecified by Maintainer | Milestone: | |
| Component: | Sugar | Version: | Unspecified |
| Severity: | Unspecified | Keywords: | |
| Cc: | Distribution/OS: | Unspecified | |
| Bug Status: | Unconfirmed |
Description
On OLPC XO-4 running OLPC 13.1.0 build 16, this command sets the volume to 0:
python -c "from gi.repository import SugarExt; SugarExt.VolumeAlsa().set_volume(80)"
(check by running "alsamixer" in another window and watching the effect on the PCM mixer)
Need to check which units are reported by alsmixer (I think its %) and which units are taken as input by VolumeAlsa. Setting the volume to 98 via sugarext results in it being set as 49 in alsamixer.
Change History (2)
comment:1 Changed 10 years ago by dsd
- Resolution set to notsugar
- Status changed from new to closed
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In the end this was a kernel bug.
SugarExt sets its values on a linear scale, and alsamixer reads them on a logarithmic scale (dB). And because the kernel had almost 1000dBs of range (oops), setting 80% on a linear scale was actually to 0 on the logarithmic scale. The problem could even be seen in amixer vs alsamixer (taking sugar out of the equation).
Having shuffled mixers around in the latest XO-4 kernel, things are now working.