My board is the HIFIBERRY DAC+ ADC PRO, running the lately updated Raspberry Pi OS bookworm with default config.txt settings.
On the Raspberry Pi 5: aplay reports a 'period_size' of 512, which is very small and could not change to a large value.
On the Raspberry Pi 4: aplay reports a 'period_size' of 16384, which is normal.
According to the description in pyalsaaudio (https://larsimmisch.github.io/pyalsaaudio/terminology.html), the period_size in ALSA (Advanced Linux Sound Architecture) affects the interrupt interval and determines how often the user's program needs to read or write data to the ALSA data buffer.
I have several Python scripts using pyalsaaudio that set the period_size to a large value like 8192, and they work fine on Raspberry Pi 4 with Pi Bookworm OS. However, these Python scripts do not function properly on Raspberry Pi 5 with the same Pi Bookworm OS. After several hours of debugging, I discovered that the maximum value for period_size is limited to 512.
My hypothesis is that the Raspberry Pi 5 kernel or the RP1 chip restricts the maximum value of period_size.
Also try the Raspberry Pi OS Lite, results are the same as GUI version.
See the following command log:
--------------------------------RPi5-------------------------------------------
$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: vc4hdmi0 [vc4-hdmi-0], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: vc4hdmi1 [vc4-hdmi-1], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 2: sndrpihifiberry [snd_rpi_hifiberry_dacplusadcpro], device 0: HiFiBerry DAC+ADC Pro HiFi multicodec-0 [HiFiBerry DAC+ADC Pro HiFi multicodec-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
$ sox -V -r 48000 -n -b 32 -c 2 sin_1K_32bit.wav synth 30 sin 1000 vol -10dB
$ aplay -D hw:CARD=sndrpihifiberry,DEV=0 -v sin_1K_32bit.wav
Playing WAVE 'sin_1K_32bit.wav' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo
Hardware PCM card 2 'snd_rpi_hifiberry_dacplusadcpro' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S32_LE
subformat : STD
channels : 2
rate : 48000
exact rate : 48000 (384000/8)
msbits : 32
buffer_size : 24064
period_size : 512
period_time : 10666
tstamp_mode : NONE
tstamp_type : MONOTONIC
period_step : 1
avail_min : 512
period_event : 0
start_threshold : 24064
stop_threshold : 24064
silence_threshold: 0
silence_size : 0
boundary : 6773413839565225984
appl_ptr : 0
hw_ptr : 0
$ aplay -D hw:CARD=sndrpihifiberry,DEV=0 --period-size=32768 -v sin_1K_32bit.wav
Playing WAVE 'sin_1K_32bit.wav' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo
Hardware PCM card 2 'snd_rpi_hifiberry_dacplusadcpro' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S32_LE
subformat : STD
channels : 2
rate : 48000
exact rate : 48000 (384000/8)
msbits : 32
buffer_size : 24064
period_size : 512
period_time : 10666
tstamp_mode : NONE
tstamp_type : MONOTONIC
period_step : 1
avail_min : 512
period_event : 0
start_threshold : 24064
stop_threshold : 24064
silence_threshold: 0
silence_size : 0
boundary : 6773413839565225984
appl_ptr : 0
hw_ptr : 0
--------------------------------RPi4-------------------------------------------
$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: vc4hdmi0 [vc4-hdmi-0], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: vc4hdmi1 [vc4-hdmi-1], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 2: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 3: sndrpihifiberry [snd_rpi_hifiberry_dacplusadcpro], device 0: HiFiBerry DAC+ADC Pro HiFi multicodec-0 [HiFiBerry DAC+ADC Pro HiFi multicodec-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
$ aplay -D hw:CARD=sndrpihifiberry,DEV=0 -v sin_1K_32bit.wav
Playing WAVE 'sin_1K_32bit.wav' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo
Hardware PCM card 3 'snd_rpi_hifiberry_dacplusadcpro' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S32_LE
subformat : STD
channels : 2
rate : 48000
exact rate : 48000 (384000/8)
msbits : 32
buffer_size : 24000
period_size : 6000
period_time : 125000
tstamp_mode : NONE
tstamp_type : MONOTONIC
period_step : 1
avail_min : 6000
period_event : 0
start_threshold : 24000
stop_threshold : 24000
silence_threshold: 0
silence_size : 0
boundary : 6755399441055744000
appl_ptr : 0
hw_ptr : 0
$ aplay -D hw:CARD=sndrpihifiberry,DEV=0 --period-size=32768 -v sin_1K_32bit.wav
Playing WAVE 'sin_1K_32bit.wav' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo
Hardware PCM card 3 'snd_rpi_hifiberry_dacplusadcpro' device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S32_LE
subformat : STD
channels : 2
rate : 48000
exact rate : 48000 (384000/8)
msbits : 32
buffer_size : 65536
period_size : 32768
period_time : 682666
tstamp_mode : NONE
tstamp_type : MONOTONIC
period_step : 1
avail_min : 32768
period_event : 0
start_threshold : 65536
stop_threshold : 65536
silence_threshold: 0
silence_size : 0
boundary : 4611686018427387904
appl_ptr : 0
hw_ptr : 0
