alsa-project/alsa-lib issue #285 was edited from bondagit:

If I try the latency test application ([test/latency.c](https://github.com/alsa-project/alsa-lib/blob/master/test/latency.c)) using a **Linux Kernel 5.9.x** with alsa-lib v1.2.4 on the following audio card: _PCH [HDA Intel PCH], device 1: ALC269VC Analog [ALC269VC Analog]_ (for example) I get the following result:

``` sudo ./latency -C hw:1 -P hw:1 -f S16_LE -r 48000 -c 2 -s 10 -m 128 -M 128 Scheduler set to Round Robin with priority 99... Playback device is hw:1 Capture device is hw:1 Parameters are 48000Hz, S16_LE, 2 channels, non-blocking mode Poll mode: no Loop limit is 480000 frames, minimum latency = 128, maximum latency = 128 Hardware PCM card 1 'HDA Intel PCH' device 0 subdevice 0 Its setup is: stream : PLAYBACK access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 128 period_size : 64 period_time : 1333 tstamp_mode : NONE tstamp_type : MONOTONIC period_step : 1 avail_min : 64 period_event : 0 start_threshold : 2147483647 stop_threshold : 128 silence_threshold: 0 silence_size : 0 boundary : 4611686018427387904 appl_ptr : 0 hw_ptr : 0 Hardware PCM card 1 'HDA Intel PCH' device 0 subdevice 0 Its setup is: stream : CAPTURE access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 128 period_size : 64 period_time : 1333 tstamp_mode : NONE tstamp_type : MONOTONIC period_step : 1 avail_min : 64 period_event : 0 start_threshold : 2147483647 stop_threshold : 128 silence_threshold: 0 silence_size : 0 boundary : 4611686018427387904 appl_ptr : 0 hw_ptr : 0 Trying latency 128 frames, 2666.667us, 2.666667ms (375.0000Hz) Success Playback: *** frames = 480128 *** state : RUNNING trigger_time: 1907393.672215 tstamp : 0.000000 delay : 80 avail : 48 avail_max : 64 Capture: *** frames = 480000 *** state : RUNNING trigger_time: 1907393.672215 tstamp : 0.000000 delay : 0 avail : 0 avail_max : 16 Maximum read: 16 frames Maximum read latency: 333.333us, 0.333333ms (3000.0000Hz) Hardware sync Playback time = 1907393.672215, Record time = 1907393.672215, diff = 0 ```

The tests succeeded and final state is **RUNNING**

If I try the same tests on the same audio device and distribution but with a **Linux Kernel >= 5.10.x** it fails systematically and I get:

``` sudo ./lantency -C hw:1 -P hw:1 -f S16_LE -r 48000 -c 2 -s 10 -m 128 -M 128 Scheduler set to Round Robin with priority 99... Playback device is hw:0 Capture device is hw:0 Parameters are 48000Hz, S16_LE, 2 channels, non-blocking mode Poll mode: no Loop limit is 480000 frames, minimum latency = 128, maximum latency = 128 Hardware PCM card 0 'HDA Intel PCH' device 0 subdevice 0 Its setup is: stream : PLAYBACK access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 128 period_size : 64 period_time : 1333 tstamp_mode : NONE tstamp_type : MONOTONIC period_step : 1 avail_min : 64 period_event : 0 start_threshold : 2147483647 stop_threshold : 128 silence_threshold: 0 silence_size : 0 boundary : 4611686018427387904 appl_ptr : 0 hw_ptr : 0 Hardware PCM card 0 'HDA Intel PCH' device 0 subdevice 0 Its setup is: stream : CAPTURE access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 128 period_size : 64 period_time : 1333 tstamp_mode : NONE tstamp_type : MONOTONIC period_step : 1 avail_min : 64 period_event : 0 start_threshold : 2147483647 stop_threshold : 128 silence_threshold: 0 silence_size : 0 boundary : 4611686018427387904 appl_ptr : 0 hw_ptr : 0 Trying latency 128 frames, 2666.667us, 2.666667ms (375.0000Hz) Failure Playback: *** frames = 90720 *** state : XRUN trigger_time: 967.658489 tstamp : 0.000000 delay : 0 avail : 216 avail_max : 216 Capture: *** frames = 90592 *** state : XRUN trigger_time: 967.658489 tstamp : 0.000000 delay : 0 avail : 88 avail_max : 88 Maximum read: 16 frames Maximum read latency: 333.333us, 0.333333ms (3000.0000Hz) Hardware sync ```

I get an **XRUN** during the test execution. I can reproduce the same error on multiple boards for multiple audio cards and on different Linux distribution just changing the Linux kernel version. The problem was originally reported at: [AES67 Linux daemon: Latency test fails with Linux kernel starting from 5.10.0x](https://github.com/bondagit/aes67-linux-daemon/issues/79)

I am interested in testing a with low latency (-m 128 -M 128). My guess is that something changed in the Linux audio core and the latency application has to be adapted. Any idea ?

Issue URL : https://github.com/alsa-project/alsa-lib/issues/285 Repository URL: https://github.com/alsa-project/alsa-lib