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@redhat.com 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