[alsa-devel] [linux-sunxi] [BUG] On Allwinner A20 Board Cubietruck distorted SPDIF opical output

[Chen-Yu Tsai]

Hi,

On Sun, Jun 10, 2018 at 1:46 AM, Markus Mitsch
<markusmitsch86 at googlemail.com> wrote:
> hi.
>
> i posted my answer wrong so here is my finding:
> i made the output work by disabling the sigma delta modulation.
> after compiling the kernel  i can output through spdif with any rate.

So it seems that the default mid-level bias current setting for PLL2
interferes with sigma-delta modulation. Similarly, the VCO bias setting
also interferes.

Try zeroing out bits 16 ~ 25 in the PLL2 tuning register (0x01c2000c)
with sigma delta on, and see if that fixes things.

I'll send out a patch later.

ChenYu

> greetings
> markus
>
> 2018-05-26 18:38 GMT+02:00 Markus Mitsch <markusmitsch86 at googlemail.com>:
>> 2018-05-26 16:57 GMT+02:00 Markus Mitsch <markusmitsch86 at googlemail.com>:
>>> 2018-05-23 17:12 GMT+02:00 Code Kipper <codekipper at gmail.com>:
>>>> Hi All,
>>>> I can see that the problem was introduced somewhere here
>>>>
>>>> DOESN'T WORK
>>>> ffc3eb6f3a83 Merge tag 'sunxi-clk-for-4.15' of
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux into
>>>> clk-next
>>>> ae74ac082886 Merge tag 'clk-v4.15-exynos-pm' of
>>>> git://git.kernel.org/pub/scm/linux/kernel/git/snawrocki/clk into
>>>> clk-next
>>>> faa865f18cb7 Merge tag 'clk-v4.15-samsung' of
>>>> git://git.kernel.org/pub/scm/linux/kernel/git/snawrocki/clk into
>>>> clk-next
>>>> f09a6b86fdae Merge tag 'clk-renesas-for-v4.15-tag1' of
>>>> git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers
>>>> into clk-next
>>>> 4328a2186e51 clk: sunxi-ng: sun4i: Export video PLLs
>>>> 553c7d5ba2fe clk: sunxi-ng: Add A83T display clocks
>>>> 7679eb20353d clk: samsung: Add a separate driver for Exynos4412 ISP clocks
>>>> 8ca8ac102484 clk: samsung: Add dt bindings for Exynos4412 ISP clock controller
>>>> 75920aac275a clk: samsung: Instantiate Exynos4412 ISP clocks only when available
>>>> 24ea78a09f89 clk: sunxi-ng: sun8i: a23: Use sigma-delta modulation for audio PLL
>>>> ee6501d69217 clk: sunxi-ng: sun6i: Use sigma-delta modulation for audio PLL
>>>> 042f7f8f9715 clk: sunxi-ng: sun5i: Use sigma-delta modulation for audio PLL
>>>> de3448519194 clk: sunxi-ng: sun4i: Use sigma-delta modulation for audio PLL
>>>> a5e3e2b2ef85 clk: sunxi-ng: sun8i: h3: Use sigma-delta modulation for audio PLL
>>>> 392ba5fafcdf clk: sunxi-ng: nm: Add support for sigma-delta modulation
>>>> 05d2eaac96d4 clk: sunxi-ng: Add sigma-delta modulation support
>>>> 4cdbc40d64d4 clk: sunxi-ng: nm: Check if requested rate is supported
>>>> by fractional clock
>>>> d51fe3ba9773 clk: sunxi-ng: sun5i: Fix bit offset of audio PLL post-divider
>>>> 4e8975cbb516 clk: samsung: exynos5433: mark PM functions as __maybe_unused
>>>> a4f21e9ceb5c clk: samsung: Remove obsolete clkdev alias support
>>>> 45d882daf88a clk: samsung: Add explicit MPLL, EPLL clkdev aliases in
>>>> S3C2443 driver
>>>> cd05417f728b clk: samsung: Rework clkdev alias handling in S3C2443 driver
>>>> efea8d377184 clk: samsung: Rework clkdev alias handling in Exynos5440 driver
>>>> 36ba48240b19 clk: samsung: Drop useless alias in Exynos5420 clk driver
>>>> 29964890f31c clk: samsung: Remove clkdev alias support in Exynos5250 clk driver
>>>> 6de08891c896 clk: samsung: Remove double assignment of CLK_ARM_CLK in
>>>> Exynos4 driver
>>>> 58f4a5ff3a62 clk: samsung: Remove clkdev alias support in Exynos4 clk driver
>>>> c9194fb623b0 clk: samsung: Remove support for obsolete Exynos4212 CPU clock
>>>> d5cd103b06f9 clk: samsung: Remove support for Exynos4212 SoCs in
>>>> Exynos CLKOUT driver
>>>> 7c4f63ec94a1 clk: sunxi-ng: a83t: Fix invalid csi-mclk mux offset
>>>> WORKS
>>>> 0a4e632b6f9d Merge branch 'clk-fixes' into clk-next
>>>>
>>>> BR,
>>>> CK
>>>>
>>>>
>>>> On 22 May 2018 at 21:27, Code Kipper <codekipper at gmail.com> wrote:
>>>>> Hi Markus,
>>>>> I've been able to reproduce this on my A31 board with linux-next(plays
>>>>> at 44100 but not at 96K)so it is an issue. I also tested the same code
>>>>> on my A64 and it worked fine, The blocks are very similar so it maybe
>>>>> a clocking issue, I'll look into this.
>>>>> BR,
>>>>> CK
>>>>>
>>>>> On 21 May 2018 at 20:17, Markus Mitsch <markusmitsch86 at googlemail.com> wrote:
>>>>>> 2018-05-21 15:17 GMT+02:00 Maxime Ripard <maxime.ripard at bootlin.com>:
>>>>>>> On Mon, May 21, 2018 at 02:43:55PM +0200, Markus Mitsch wrote:
>>>>>>>> 2018-05-21 11:43 GMT+02:00 Markus Mitsch <markusmitsch86 at googlemail.com>:
>>>>>>>> >>> Hello,
>>>>>>>> >>>
>>>>>>>> >>> i have a new problem. if i want to output sound from optical i get
>>>>>>>> >>> distorted sound. At 44.1 khz its like an old vinly, but at 48 khz and
>>>>>>>> >>> higher it is very bad. thanks in advance for your time.
>>>>>>>> >
>>>>>>>> >> Hi Markus,
>>>>>>>> >> I haven't tested it for a while but when I did it worked as high as
>>>>>>>> >> 96K with no issues. Does it work ok with the original cubietruck
>>>>>>>> >> software?,
>>>>>>>> >> CK
>>>>>>>> >
>>>>>>>> > Hello,
>>>>>>>> > i am using arch linux with mainline kernel 4.16.8. parhaps i can try
>>>>>>>> > today with official image.
>>>>>>>> > mfg
>>>>>>>>
>>>>>>>> Hi.
>>>>>>>> So, with debian image from 2014 with 3.4.79 kernel the sound is clear
>>>>>>>> up to 96 khz.
>>>>>>>
>>>>>>> You said that it is a new problem, when was it introduced? Could you
>>>>>>> bisect the issue?
>>>>>>>
>>>>>>> Maxime
>>>>>>
>>>>>> Hello.
>>>>>> I dont know since when this problem appears. When saying "new" i
>>>>>> refered to my older post. I tried to look into the dts file and the
>>>>>> code
>>>>>> but i am afraid this is a bit too high for me. I can say that the
>>>>>> analog output works, even at high sampling rates.
>>>>>> And I have read something about a clock source could be the problem.
>>>>>> I'm sorry I can't tell you any more.
>>>>>>
>>>>>> mfg
>>>>>> Markus
>>>
>>> Hello,
>>> i tried undoing part of the commit
>>> de3448519194 clk: sunxi-ng: sun4i: Use sigma-delta modulation for audio PLL
>>> by setting the value for the divider from 1 to 4 again on both places.
>>> with no success.
>>>
>>> markus
>>
>> i now had a little success. the output works!!
>> i disabled the sigma-delta support by making
>> ccu_sdm_helper_enable in drivers/clk/sunxi-ng/ccu_sdm.c  return imediately.
>>
>> markus