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Tools: Complete Guide to I Have No Sound, and I Must Hear: A Story of a Kernel Regression

2026-04-28 0 views admin
Tools: Complete Guide to I Have No Sound, and I Must Hear: A Story of a Kernel Regression

The Prologue

The Diagnosis

Deep Dive into dmesg (The 0xFFFF Error)

What is CORB and why does it matter?

Eureka: The Software "Hot-swap"

Automation

Conclusion TL;DR: After a kernel update, my 15-year-old laptop lost sound with CORB reset timeout and CORBRP = 65535 (0xFFFF). Reinstalling audio servers didn't help. GRUB parameters were ignored. The fix? Force a PCI rescan via sysfs and automate it with a systemd service. Here's the full debugging journey. I use an old laptop — an Emachines E732. It’s so ancient that its maximum RAM is 8GB. Yet, it remains my reliable workhorse. Everything was fine until a routine sudo pacman -Syu on CachyOS. Suddenly, the sound was gone. Reinstalling pulseaudio or pipewire did nothing. I hopped over to EndeavourOS, where it worked... until I switched to the linux-zen kernel. Then it died again. Eventually, the sound vanished even on LTS kernels and LiveCDs. I almost gave up and bought a USB sound card, but then I realized: a workaround must exist. Standard tools were useless. aplay -l was laconic: However, inxi -Axxz confirmed the hardware was still there: And journalctl showed the first signs of trouble: The system knew the card existed but couldn't talk to it. Here’s what didn't work: The truth was buried in dmesg. When the snd_hda_intel driver tries to wake up, it hits a wall: CORB (Command Output Ring Buffer) is the ring buffer used by the driver to send commands to the audio codec. Trying to reload the module manually (modprobe -r / modprobe) just produced the same errors with different timestamps. The device was stuck. I noticed that during a cold boot, the kernel assigned the card an address in the lower memory range: BAR 0 [mem 0xd4400000-0xd4403fff 64bit]. I decided to try a "software hot-plug" via sysfs: It worked. The dmesg output changed. Upon rescan, the kernel assigned a new memory address (BAR 0): The Realtek ALC272 codec finally responded. I first tried a udev rule, but it failed due to a race condition: udev caught the "add" event and tried to "remove" the card while the kernel was still struggling to initialize it. The stable solution is a systemd oneshot service: /etc/systemd/system/fix-audio.service LTS doesn't guarantee the absence of regressions. Sometimes, progress (new power management or resource allocation logic) forgets about 15-year-old chipsets. Why not a kernel bug report?

The hardware is 15 years old. A proper report requires a kernel bisect (dozens of re-compilations). On an 8GB laptop, that's torture. I chose the efficient workaround: a 5-minute script vs. weeks of compilation for a fix that might never be merged. Maybe the hardware is just dying?

The logs say otherwise. If it were dying, it wouldn't work stably after a rescan — it would fail randomly or not be detected at all. This is a classic software/resource allocation issue. Templates let you quickly answer FAQs or store snippets for re-use. Hide child comments as well For further actions, you may consider blocking this person and/or reporting abuse

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aplay: device_list:274: no soundcards found... aplay: device_list:274: no soundcards found... aplay: device_list:274: no soundcards found... Audio: Device-1: Intel 5 Series/3400 Series High Definition Audio vendor: Acer Incorporated ALI driver: snd_hda_intel v: kernel bus-ID: 00:1b.0 chip-ID: 8086:3b56 Audio: Device-1: Intel 5 Series/3400 Series High Definition Audio vendor: Acer Incorporated ALI driver: snd_hda_intel v: kernel bus-ID: 00:1b.0 chip-ID: 8086:3b56 Audio: Device-1: Intel 5 Series/3400 Series High Definition Audio vendor: Acer Incorporated ALI driver: snd_hda_intel v: kernel bus-ID: 00:1b.0 chip-ID: 8086:3b56 kernel: hdaudio hdaudioC0D0: no AFG or MFG node found kernel: hdaudio hdaudioC0D1: no AFG or MFG node found kernel: hdaudio hdaudioC0D0: no AFG or MFG node found kernel: hdaudio hdaudioC0D1: no AFG or MFG node found kernel: hdaudio hdaudioC0D0: no AFG or MFG node found kernel: hdaudio hdaudioC0D1: no AFG or MFG node found snd_hda_intel 0000:00:1b.0: CORB reset timeout#2, CORBRP = 65535 snd_hda_intel 0000:00:1b.0: no codecs initialized snd_hda_intel 0000:00:1b.0: CORB reset timeout#2, CORBRP = 65535 snd_hda_intel 0000:00:1b.0: no codecs initialized snd_hda_intel 0000:00:1b.0: CORB reset timeout#2, CORBRP = 65535 snd_hda_intel 0000:00:1b.0: no codecs initialized # Drop the card from the system echo 1 | sudo tee /sys/bus/pci/devices/0000:00:1b.0/remove sleep 2 # Rescan the PCI bus echo 1 | sudo tee /sys/bus/pci/rescan # Drop the card from the system echo 1 | sudo tee /sys/bus/pci/devices/0000:00:1b.0/remove sleep 2 # Rescan the PCI bus echo 1 | sudo tee /sys/bus/pci/rescan # Drop the card from the system echo 1 | sudo tee /sys/bus/pci/devices/0000:00:1b.0/remove sleep 2 # Rescan the PCI bus echo 1 | sudo tee /sys/bus/pci/rescan pci 0000:00:1b.0: BAR 0 [mem 0x23c000000-0x23c003fff 64bit]: assigned snd_hda_intel 0000:00:1b.0: bound 0000:00:02.0 input: HDA Intel MID Mic as /devices/pci0000:00/.../input24 pci 0000:00:1b.0: BAR 0 [mem 0x23c000000-0x23c003fff 64bit]: assigned snd_hda_intel 0000:00:1b.0: bound 0000:00:02.0 input: HDA Intel MID Mic as /devices/pci0000:00/.../input24 pci 0000:00:1b.0: BAR 0 [mem 0x23c000000-0x23c003fff 64bit]: assigned snd_hda_intel 0000:00:1b.0: bound 0000:00:02.0 input: HDA Intel MID Mic as /devices/pci0000:00/.../input24 [Unit] Description=Fix Audio PCI Rescan After=multi-user.target [Service] Type=oneshot ExecStartPre=/usr/bin/sh -c 'echo 1 > /sys/bus/pci/devices/0000:00:1b.0/remove' ExecStart=/usr/bin/sh -c 'sleep 2 && echo 1 > /sys/bus/pci/rescan' RemainAfterExit=yes [Install] WantedBy=multi-user.target [Unit] Description=Fix Audio PCI Rescan After=multi-user.target [Service] Type=oneshot ExecStartPre=/usr/bin/sh -c 'echo 1 > /sys/bus/pci/devices/0000:00:1b.0/remove' ExecStart=/usr/bin/sh -c 'sleep 2 && echo 1 > /sys/bus/pci/rescan' RemainAfterExit=yes [Install] WantedBy=multi-user.target [Unit] Description=Fix Audio PCI Rescan After=multi-user.target [Service] Type=oneshot ExecStartPre=/usr/bin/sh -c 'echo 1 > /sys/bus/pci/devices/0000:00:1b.0/remove' ExecStart=/usr/bin/sh -c 'sleep 2 && echo 1 > /sys/bus/pci/rescan' RemainAfterExit=yes [Install] WantedBy=multi-user.target - User-space fixes: Reinstalling PipeWire or tweaking alsamixer. If ALSA can't see the card, software sliders are useless. - Module parameters: Adding model=auto or enable=1 to modprobe.d. These change driver behavior but can't fix PCI resource allocation errors. - Kernel parameters: pci=nocrs, pci=nomsi, pcie_aspm=off in GRUB. The kernel stubbornly ignored these crutches. - Timeout means the hardware isn't responding to a "reset" command. - CORBRP = 65535 (0xFFFF) is the key. In the hardware world, "all ones" usually means the bus is hung or the device is physically inaccessible/unpowered. - Remove the device from the PCI tree. - Force the kernel to rescan the bus. - Before: mem 0xd4400000 (lower memory, high chance of conflicts with old BIOS). - After: mem 0x23c000000 (moved above the 4GB boundary). - 0xFFFF in logs is often a cry for help from the PCI bus, not hardware death. - Addresses matter. Moving a device above 4GB can bypass BIOS resource conflicts. - Don't rush to buy USB dongles. Sometimes Linux just needs you to "unplug and replug" the device via software.

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