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Buildroot 2021 + Dac+

mchalain

May 29, 2021 12:51

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Hello,

did you test dac+ (or amp2) with Linux 5.10 from raspberry ?

I build an image with BuildRoot 2021-02 which use linux-custom 5.10.

The overlay (from /proc/device-tree) is corresponding to the one in the kernel linux. The pcm512x driver contains the patch about SCLK, and it uses the I2C address 0x4d. The hifiberry-dacplus is loaded with dependencies, and it uses the pcm512x driver.

Alsamixer gives some entries (Analogue, Analogue Playback Boost,...) and all looks fines.

aplay -L shows the card and speaker-test request 2 channels. BUT no sound from the speaker, just a "pok" when the test is stopping.

I tested with hifiberryOS and the hardware runs correctly.

Do you have any idea ?

I saw a patch from hifiberryOS about pcm512x to switch off the PM. Is it mandatory ?

Regards,
Marc.

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6 comments

• 0
  
  HiFiBerry team May 29, 2021 13:23

  The normal Raspberry Pi OS uses Linux 5.10 already. Therefore in general it should work fine. However, we didn't test it with Buildroot yet. We never use the standard kernel that comes with buildroot, but always use one that we tested - currently 5.4
  You should be able to change the kernel to 5.4 in the configuration.

• 0
  
  mchalain June 07, 2021 07:12

  Hello

  I tested with kernel 5.4 and I have the same trouble.

  I had the power on the left channel, but without sound, and nothing on the right channel.

  I changed my hifiberrry amp2 card for a hifiberry miniamp. On the same system (buildroot 2021 02 + kernel 5.4) I modified the config.txt to load the hifiberry-dac dtbo instead the hifiberry-dacplus. Tata.... I have a correct sound on the both channels.

  I saw another difference, the pcm512x module is automatically loaded with hifiberry-dac dtbo. I have to loaded manually with hifiberry-dacplus.

  I checked the hifiberry-dacplus.dtbo. This is the version build with the kernel 5.4 and 5.10 and the same used with hifiberryos (to check I regenerate the dts from the dtbo with dtc).

  Did you change some thing inside the hifiberry-dacplus driver which impacts the amp2 ?

  Best regard,

  Marc Chalain.

• 0
  
  mchalain June 07, 2021 07:13

  Do you set something with asound.conf ?

• 0
  
  HiFiBerry team June 07, 2021 08:17

  If it works with the Miniamp, the asound.conf seems to be ok. 
  
  No patches should be necessary. You might simply try the configuration we're using for HiFiBerryOS (same kernel, init system, ...)

• 0
  
  mchalain June 07, 2021 13:24

  Just for information, it is complicated to debug with hifiberryOS: detect-hifberry modify automatically the config.txt, remove the miniuart-bt and we have to remove /opt/hifiberry to keep the modifications.

  A good idea may be to check miniuart-bt in the config.txt and to keep it with detect-hifiberry... :)

• 0
  
  HiFiBerry team June 07, 2021 19:29

  There a good reason we remove this: BT audio on miniuart just doesn't work reliably. It's not supported and we don't plan to support this ever.