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| author | Andi Shyti <andi.shyti@linux.intel.com> | 2026-08-22 14:19:12 +0200 |
|---|---|---|
| committer | Andi Shyti <andi.shyti@linux.intel.com> | 2026-08-22 14:19:34 +0200 |
| commit | d576a9561a1c80ae593539fb0ce0743d66825ac2 (patch) | |
| tree | 68f6de7e06b350afa42edeea2f7f33f086014597 /Documentation/power/shutdown-debugging.rst | |
| download | linux-stable-d576a9561a1c80ae593539fb0ce0743d66825ac2.tar.gz linux-stable-d576a9561a1c80ae593539fb0ce0743d66825ac2.zip | |
Merge tag 'rust-i2c-for-7.3' into i2c/i2cgrafted
i2c: rust: mark I2cAdapter methods as inline
A single cleanup for the Rust I2C abstractions, targeting 7.3.
`I2cAdapter::get`, `inc_ref`, and `dec_ref` are trivial wrappers around
`i2c_get_adapter`/`i2c_put_adapter` and were showing up as their own
symbols in the build. Mark them `#[inline]` so they get folded into
their callers instead.
Signed-off-by: Igor Korotin <igor.korotin@linux.dev>
* tag 'rust-i2c-for-7.3':
i2c: rust: mark I2cAdapter methods as inline
Diffstat (limited to 'Documentation/power/shutdown-debugging.rst')
| -rw-r--r-- | Documentation/power/shutdown-debugging.rst | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/Documentation/power/shutdown-debugging.rst b/Documentation/power/shutdown-debugging.rst new file mode 100644 index 000000000..c510122e0 --- /dev/null +++ b/Documentation/power/shutdown-debugging.rst @@ -0,0 +1,53 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Debugging Kernel Shutdown Hangs with pstore ++++++++++++++++++++++++++++++++++++++++++++ + +Overview +======== +If the system hangs while shutting down, the kernel logs may need to be +retrieved to debug the issue. + +On systems that have a UART available, it is best to configure the kernel to use +this UART for kernel console output. + +If a UART isn't available, the ``pstore`` subsystem provides a mechanism to +persist this data across a system reset, allowing it to be retrieved on the next +boot. + +Kernel Configuration +==================== +To enable ``pstore`` and enable saving kernel ring buffer logs, set the +following kernel configuration options: + +* ``CONFIG_PSTORE=y`` +* ``CONFIG_PSTORE_CONSOLE=y`` + +Additionally, enable a backend to store the data. Depending upon your platform +some potential options include: + +* ``CONFIG_EFI_VARS_PSTORE=y`` +* ``CONFIG_PSTORE_RAM=y`` +* ``CONFIG_CHROMEOS_PSTORE=y`` +* ``CONFIG_PSTORE_BLK=y`` + +Kernel Command-line Parameters +============================== +Add these parameters to your kernel command line: + +* ``printk.always_kmsg_dump=Y`` + * Forces the kernel to dump the entire message buffer to pstore during + shutdown +* ``efi_pstore.pstore_disable=N`` + * For EFI-based systems, ensures the EFI backend is active + +Userspace Interaction and Log Retrieval +======================================= +On the next boot after a hang, pstore logs will be available in the pstore +filesystem (``/sys/fs/pstore``) and can be retrieved by userspace. + +On systemd systems, the ``systemd-pstore`` service will help do the following: + +#. Locate pstore data in ``/sys/fs/pstore`` +#. Read and save it to ``/var/lib/systemd/pstore`` +#. Clear pstore data for the next event |
