| 2010-05-12 13:06:39 |
Hugh Warrington |
description |
I am listening to music using Rhythmbox. To adjust the volume I use the vol -/+ keys built in to my Microsoft Natural 4000 keyboard. This arrangement worked fine in 9.10. A pop-up OSD in the top-right of the screen appeared whenever I changed the volume. The full range of this indicator (from empty to full) correctly corresponded to the full range of silence to maximum volume output over my headphones.
Since upgrading to 10.04, the control behaves as follows. At the lowest setting, I get no sound output, as expected. With one press of the vol+ key, the bar becomes one notch full (I note there appear to be 18 discrete values that the OSD can indicate). However, the sound output is fairly loud: around half of the maximum output. After two presses of the vol+ key, the bar is only about 10% full, but the sound output is at or near the maximum (uncomfortably loud through my headphones). Successive presses of vol+ continue to raise the indicated volume, but have no discernible effect on the output volume.
I can watch what's going on in alsamixer while I press the vol -/+ keys. At volume zero, the bars marked Master Front, PCM and Front are all on zero, and are marked as muted. On volume notch one (after one press of vol+), those channels are marked as unmuted, and have respective values 0, 98, 60. After two presses 0, 98, 88. After three presses 6, 98, 100. Successive presses just increase the Master Front value.
If I manually scale the PCM and Front columns using the arrow keys, I get the expected response. i.e. perceived volume output is proportional to the product of PCM and Front.
I'm using a Dell Inspiron 546. uname -a gives:
Linux alma 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 17:01:44 UTC 2009 x86_64 GNU/Linux
The bits of lspci that I think are relevant:
00:14.2 Audio device: ATI Technologies Inc SBx00 Azalia (Intel HDA)
01:05.1 Audio device: ATI Technologies Inc RS780 Azalia controller
Expected behaviour: output volume scales linearly with the scale displayed on screen. |
I am listening to music using Rhythmbox. To adjust the volume I use the vol -/+ keys built in to my Microsoft Natural 4000 keyboard. This arrangement worked fine in 9.10. A pop-up OSD in the top-right of the screen appeared whenever I changed the volume. The full range of this indicator (from empty to full) correctly corresponded to the full range of silence to maximum volume output over my headphones.
Since upgrading to 10.04, the control behaves as follows. At the lowest setting, I get no sound output, as expected. With one press of the vol+ key, the bar becomes one notch full (I note there appear to be 18 discrete values that the OSD can indicate). However, the sound output is fairly loud: around half of the maximum output. After two presses of the vol+ key, the bar is only about 10% full, but the sound output is at or near the maximum (uncomfortably loud through my headphones). Successive presses of vol+ continue to raise the indicated volume, but have no discernible effect on the output volume.
I can watch what's going on in alsamixer while I press the vol -/+ keys. (side note: alsamixer says 'Card: HDA ATI SB' and 'Chip: VIA VT1708S'). At volume zero, the bars marked Master Front, PCM and Front are all on zero, and are marked as muted. On volume notch one (after one press of vol+), those channels are marked as unmuted, and have respective values 0, 98, 60. After two presses 0, 98, 88. After three presses 6, 98, 100. Successive presses just increase the Master Front value.
If I manually scale the PCM and Front columns using the arrow keys, I get the expected response. i.e. perceived volume output is proportional to the product of PCM and Front.
I'm using a Dell Inspiron 546. uname -a gives:
Linux alma 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 17:01:44 UTC 2009 x86_64 GNU/Linux
The bits of lspci that I think are relevant:
00:14.2 Audio device: ATI Technologies Inc SBx00 Azalia (Intel HDA)
01:05.1 Audio device: ATI Technologies Inc RS780 Azalia controller
Expected behaviour: output volume scales linearly with the scale displayed on screen.
|
|
