Hello Hans, Daniel,
Thank you for reviewing and comment.
On 2019/08/26 18:09, Hans de Goede wrote:
Hi,
On 26-08-19 04:53, Daniel Drake wrote:
On Mon, Aug 26, 2019 at 1:38 AM Hans de Goede <hdegoede@xxxxxxxxxx>
wrote:
On 24-08-19 23:04, Katsuhiro Suzuki wrote:
This patch limits Headphone mixer volume to 4 from 7.
Because output sound suddenly becomes very loudly with many noise if
set volume over 4.
That sounds like something that should be limited in UCM.
Higher then 4 not working matches my experience, see this comment from
the UCM file: alsa-lib/src/conf/ucm/codecs/es8316/EnableSeq.conf :
# Set HP mixer vol to -6 dB (4/7) louder does not work
cset "name='Headphone Mixer Volume' 4"
What does "does not work" mean more precisely?
IIRC garbled sound.
I checked the spec, there is indeed something wrong in the kernel
driver here.
The db scale is not a simple scale as the kernel source suggests.
Instead it is:
0000 – -12dB
0001 – -10.5dB
0010 – -9dB
0011 – -7.5dB
0100 – -6dB
1000 – -4.5dB
1001 – -3dB
1010 – -1.5dB
1011 – 0dB
So perhaps we can fix the kernel to follow this table and then use UCM
to limit the volume if its too high on a given platform?
Yes that sounds like the right thing to do. Katsuhiro can you confirm that
using this table allows using the full scale ? note that the full scale now
has 9 steps rather then 8.
I've finished testing this table on my board (RockPro64).
Every values work well without garbled sound.
I checked address 0x16 register via /sys/kernel/debug/regmap too.
The register values and dB (get from alsamixer) are the following if
I increase headphone volume to max from min.
reg dB
0x16 scale
------------
0x00 -12.00
0x11 -10.50
0x22 -9.00
0x33 -7.50
0x44 -6.00
0x88 -4.50
0x99 -3.00
0xaa -1.50
0xbb 0.00
And I found other problem, current code is inverted L/R volume.
It's only in Headphone "mixer" volume. It seems Headphone "master"
volume works correctly.
I'll fix these problems and send V2 patch set.
Regards,
Hans
Best Regards,
Katsuhiro Suzuki
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