I generally use the RT-LTS kernels and have noticed severe audio drop out and hugely excessive xruns in recent kernels.
Starting a session with kernel 5.4.106-rt54-MANJARO from GRUB gives me a beautifully smooth system like I’m used to so I’m sure it’s the kernel which is at fault.
Issues have been observed and seem about the same in the current RT-LTS kernel, which is 5.9-rt, and on the Liquorix kernel built to days ago, which is version 5.11.14-lqx. Thus the issue isn’t only with the RT version maintained by Manjaro/Arch and it has persisted for multiple kernel updates.
I use the laptop for some audio production, digital DJing, video editing etc as hobbies and as such I always have Jack running and for the analogue audio use the PA-Jack bridge. With the good 5.4-rt kernel I may see 1 or 2 xruns in an hour of moderate usage but not observe anything on actual audio output. With the problem kernels I can boot the system and leave it completely idle and get over 100 xruns in an hour. I also get audio dropout with doing nothing more than watching a video on VLC which would play perfectly smooth previously. Dropouts observed on both internal analogue audio (via PA-Jack-ALSA and through purely Jack-ALSA) and over the HDMI (via PA-ALSA with no Jack but Jack still running for the analogue, unused path.)
In kernel 5.7 there was a kernel change to the driver for managing CPU (governor, staging etc) and I have a 5th generation i7 mobile CPU. This is the most recent that should go to the new governor in these kernels (named intel_cpufreq, not to be confused with the old acpi-cpufreq.) Manually forcing 5.9-rt to use intel_pstate (which was used previously) didn’t make any difference. 5.11-lqx seems to load acpi-cpufreq instead of intel_cpufreq but also shows the same issues. This was the only obvious change in the kernel around that time I could think to try see if it may be a culprit.
Not tested an external audio interface (but I do have a DJ controller with one built in but haven’t found the time to test and compare.) I haven’t tried with Jack server stopped as audio dropouts while playing video aren’t all the time so would be rather time consuming to see if it still occurs then.
Is it possible to lock a kernel so it will never be removed in an upgrade? I currently have the system set to keep current and previous two kernels. I would like to lock 5.4-rt until this is fixed.
What more can I do to help this get fixed upstream?
System:
Kernel: 5.4.106-rt54-MANJARO x86_64 bits: 64 compiler: gcc v: 10.2.0
parameters: BOOT_IMAGE=/boot/vmlinuz-5.4-rt-x86_64
root=UUID=061bfd5e-d64c-49e5-9fbb-53062d0aa575 rw quiet
resume=UUID=77edc4d2-06b7-4b8c-af4c-c7757bbe342f
Desktop: Xfce 4.16.0 tk: Gtk 3.24.24 info: xfce4-panel wm: xfwm4 vt: 7
dm: LightDM 1.30.0 Distro: Manjaro Linux base: Arch Linux
Machine:
Type: Laptop System: Hewlett-Packard product: HP EliteBook 840 G2
v: A3009D410303 serial: <filter> Chassis: type: 10 serial: <filter>
Mobo: Hewlett-Packard model: 2216 v: KBC Version 96.5B serial: <filter>
UEFI: Hewlett-Packard v: M71 Ver. 01.27 date: 07/12/2018
Battery:
ID-1: BAT0 charge: 32.4 Wh (100.0%) condition: 32.4/32.4 Wh (100.0%)
volts: 12.7 min: 11.4 model: Hewlett-Packard Primary type: Li-ion
serial: <filter> status: Full
Memory:
RAM: total: 15.04 GiB used: 2.69 GiB (17.9%)
RAM Report: permissions: Unable to run dmidecode. Root privileges required.
CPU:
Info: Dual Core model: Intel Core i7-5500U bits: 64 type: MT MCP
arch: Broadwell family: 6 model-id: 3D (61) stepping: 4 microcode: 2F cache:
L2: 4 MiB bogomips: 19163
Speed: 2402 MHz min/max: 500/3000 MHz Core speeds (MHz): 1: 2402 2: 2416
3: 2396 4: 2655
Flags: 3dnowprefetch abm acpi adx aes aperfmperf apic arat arch_perfmon avx
avx2 bmi1 bmi2 bts clflush cmov constant_tsc cpuid cpuid_fault cx16 cx8 de
ds_cpl dtes64 dtherm dts epb ept ept_ad erms est f16c flexpriority flush_l1d
fma fpu fsgsbase fxsr ht ibpb ibrs ida intel_pt invpcid invpcid_single
lahf_lm lm mca mce md_clear mmx monitor movbe msr mtrr nonstop_tsc nopl nx
pae pat pbe pcid pclmulqdq pdcm pdpe1gb pebs pge pln pni popcnt pse pse36
pti pts rdrand rdseed rdtscp rep_good sdbg sep smap smep ss ssbd sse sse2
sse4_1 sse4_2 ssse3 stibp syscall tm tm2 tpr_shadow tsc tsc_adjust
tsc_deadline_timer vme vmx vnmi vpid x2apic xsave xsaveopt xtopology xtpr
Vulnerabilities: Type: itlb_multihit status: KVM: Split huge pages
Type: l1tf
mitigation: PTE Inversion; VMX: conditional cache flushes, SMT vulnerable
Type: mds mitigation: Clear CPU buffers; SMT vulnerable
Type: meltdown mitigation: PTI
Type: spec_store_bypass
mitigation: Speculative Store Bypass disabled via prctl and seccomp
Type: spectre_v1
mitigation: usercopy/swapgs barriers and __user pointer sanitization
Type: spectre_v2 mitigation: Full generic retpoline, IBPB: conditional,
IBRS_FW, STIBP: conditional, RSB filling
Type: srbds mitigation: Microcode
Type: tsx_async_abort status: Not affected
Graphics:
Device-1: Intel HD Graphics 5500
vendor: Hewlett-Packard ZBook 15u G2 Mobile Workstation driver: i915
v: kernel bus-ID: 00:02.0 chip-ID: 8086:1616 class-ID: 0300
Display: x11 server: X.Org 1.20.11 driver: loaded: intel display-ID: :0.0
screens: 1
Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 508x285mm (20.0x11.2")
s-diag: 582mm (22.9")
Monitor-1: eDP1 res: 1920x1080 hz: 60 dpi: 157 size: 310x170mm (12.2x6.7")
diag: 354mm (13.9")
OpenGL: renderer: Mesa Intel HD Graphics 5500 (BDW GT2) v: 4.6 Mesa 21.0.2
direct render: Yes
Audio:
Device-1: Intel Broadwell-U Audio vendor: Hewlett-Packard
driver: snd_hda_intel v: kernel bus-ID: 00:03.0 chip-ID: 8086:160c
class-ID: 0403
Device-2: Intel Wildcat Point-LP High Definition Audio
vendor: Hewlett-Packard driver: snd_hda_intel v: kernel bus-ID: 00:1b.0
chip-ID: 8086:9ca0 class-ID: 0403
Sound Server-1: ALSA v: k5.4.106-rt54-MANJARO running: yes
Sound Server-2: sndio v: N/A running: no
Sound Server-3: JACK v: 1.9.17 running: yes
Sound Server-4: PulseAudio v: 14.2 running: yes
Sound Server-5: PipeWire v: 0.3.25 running: no
Network:
Device-1: Intel Ethernet I218-LM vendor: Hewlett-Packard driver: e1000e
v: 3.2.6-k port: 5080 bus-ID: 00:19.0 chip-ID: 8086:15a2 class-ID: 0200
IF: enp0s25 state: down mac: <filter>
Device-2: Intel Wireless 7265 driver: iwlwifi v: kernel port: ef80
bus-ID: 03:00.0 chip-ID: 8086:095a class-ID: 0280
IF: wlo1 state: up mac: <filter>
IP v4: <filter> type: dynamic noprefixroute scope: global
broadcast: <filter>
IP v6: <filter> type: noprefixroute scope: link
WAN IP: <filter>
Bluetooth:
Message: No bluetooth data found.
Logical:
Message: No logical block device data found.
RAID:
Message: No RAID data found.
Drives:
Local Storage: total: 3.64 TiB used: 2.86 TiB (78.5%)
SMART Message: Unable to run smartctl. Root privileges required.
ID-1: /dev/sda maj-min: 8:0 vendor: Samsung model: SSD 850 EVO 4TB
size: 3.64 TiB block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s
rotation: SSD serial: <filter> rev: 2B6Q scheme: GPT
Message: No optical or floppy data found.
Partition:
ID-1: / raw-size: 61.04 GiB size: 59.83 GiB (98.02%) used: 34.24 GiB (57.2%)
fs: ext4 dev: /dev/sda3 maj-min: 8:3 label: N/A
uuid: 061bfd5e-d64c-49e5-9fbb-53062d0aa575
ID-2: /boot/efi raw-size: 497 MiB size: 496 MiB (99.80%)
used: 49.9 MiB (10.1%) fs: vfat dev: /dev/sda1 maj-min: 8:1 label: N/A
uuid: A27D-524E
ID-3: /run/media/me/data raw-size: 3.19 TiB size: 3.14 TiB (98.40%)
used: 2.82 TiB (89.9%) fs: ext4 dev: /dev/sda6 maj-min: 8:6 label: N/A
uuid: be07e4f2-9d3f-4157-b3af-bb4ba093d0c3
Swap:
Kernel: swappiness: 10 (default 60) cache-pressure: 100 (default)
ID-1: swap-1 type: partition size: 15.26 GiB used: 0 KiB (0.0%) priority: -2
dev: /dev/sda5 maj-min: 8:5 label: N/A
uuid: 77edc4d2-06b7-4b8c-af4c-c7757bbe342f
Unmounted:
ID-1: /dev/sda2 maj-min: 8:2 size: 61.04 GiB fs: ext4 label: N/A
uuid: 3ffef06f-042c-4c31-85a9-df054c4fffe8
ID-2: /dev/sda4 maj-min: 8:4 size: 61.04 GiB fs: ext4 label: N/A
uuid: 1ebebcd8-bc3c-401c-b148-439e932188ee
USB:
Hub-1: 1-0:1 info: Full speed (or root) Hub ports: 3 rev: 2.0
speed: 480 Mb/s chip-ID: 1d6b:0002 class-ID: 0900
Hub-2: 1-1:2 info: Intel Integrated Hub ports: 8 rev: 2.0 speed: 480 Mb/s
chip-ID: 8087:8001 class-ID: 0900
Hub-3: 2-0:1 info: Full speed (or root) Hub ports: 11 rev: 2.0
speed: 480 Mb/s chip-ID: 1d6b:0002 class-ID: 0900
Hub-4: 2-3:2 info: Microchip (formerly SMSC) Hub ports: 4 rev: 2.1
speed: 480 Mb/s chip-ID: 0424:2134 class-ID: 0900
Hub-5: 3-0:1 info: Full speed (or root) Hub ports: 4 rev: 3.0 speed: 5 Gb/s
chip-ID: 1d6b:0003 class-ID: 0900
Hub-6: 3-3:2 info: Microchip (formerly SMSC) Hub ports: 4 rev: 3.0
speed: 5 Gb/s chip-ID: 0424:5534 class-ID: 0900
Sensors:
System Temperatures: cpu: 58.0 C mobo: 0.0 C
Fan Speeds (RPM): N/A
Info:
Processes: 193 Uptime: 1h 23m wakeups: 1 Init: systemd v: 247
tool: systemctl Compilers: gcc: 10.2.0 Packages: pacman: 2036 lib: 479
Shell: Bash v: 5.1.0 running-in: xfce4-terminal inxi: 3.3.04