Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst
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Pull sound fixes from Takashi Iwai:
"Here are a bunch of updates, but there should be no big surprises;
mostly device-specific quirks and fix-ups or non-code changes:
- Quirks for ASoC AMD, HD-audio and USB-audio
- Fixes in ASoC fsl, rockchip, renesas, aw codecs
- Fixes for USB-audio packet handling in the implicit feedback mode
- Updates of SPDX license IDs in some files"
* tag 'sound-fix-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (28 commits)
ASoC: rockchip: i2s-tdm: Use param rate if not provided by set_sysclk
ALSA: hda/hdmi: Add quirk for TUXEDO IBS14G6
ASoC: dt-bindings: asahi-kasei,ak5558: Fix the supply names
ASoC: dt-bindings: asahi-kasei,ak4458: Fix the supply names
ASoC: dt-bindings: asahi-kasei,ak4458: set unevaluatedProperties:false
ASoC: amd: amd_sdw: add machine driver quirk for Lenovo models
ASoC: amd: acp: Add ACP7.0 match entries for Realtek parts
ALSA: echoaudio: Add SPDX ids to some files
ALSA: isa: Add SPDX id lines to some files
ALSA: core: Add SPDX license id to files
ASoC: tas2783A: add explicit port prepare handling
ASoC: renesas: rz-ssi: Fix playback and capture
ALSA: hda/realtek: Fix headset mic on ASUS Zenbook 14 UX3405MA
ALSA: hda/conexant: Fix headphone jack handling on Acer Swift SF314
ASoC: qcom: sm8250: Add quinary MI2S support
ASoC: amd: yc: Add DMI quirk for ASUS Vivobook Pro 15X M6501RR
ALSA: usb-audio: Avoid potentially repeated XRUN error messages
ALSA: usb-audio: Add sanity check for OOB writes at silencing
ALSA: usb-audio: Optimize the copy of packet sizes for implicit fb handling
ALSA: usb-audio: Update the number of packets properly at receiving
...
Pull drm fixes from Dave Airlie:
"This is the fixes and cleanups for the end of the merge window, it's
nearly all amdgpu, with some amdkfd, then a pagemap core fix, i915/xe
display fixes, and some xe driver fixes.
Nothing seems out of the ordinary, except amdgpu is a little more
volume than usual.
pagemap:
- drm/pagemap: pass pagemap_addr by reference
amdgpu:
- DML 2.1 fixes
- Panel replay fixes
- Display writeback fixes
- MES 11 old firmware compat fix
- DC CRC improvements
- DPIA fixes
- XGMI fixes
- ASPM fix
- SMU feature bit handling fixes
- DC LUT fixes
- RAS fixes
- Misc memory leak in error path fixes
- SDMA queue reset fixes
- PG handling fixes
- 5 level GPUVM page table fix
- SR-IOV fix
- Queue reset fix
- SMU 13.x fixes
- DC resume lag fix
- MPO fixes
- DCN 3.6 fix
- VSDB fixes
- HWSS clean up
- Replay fixes
- DCE cursor fixes
- DCN 3.5 SR DDR5 latency fixes
- HPD fixes
- Error path unwind fixes
- SMU13/14 mode1 reset fixes
- PSP 15 updates
- SMU 15 updates
- Sync fix in amdgpu_dma_buf_move_notify()
- HAINAN fix
- PSP 13.x fix
- GPUVM locking fix
- Fixes for DC analog support
- DC FAMS fixes
- DML 2.1 fixes
- eDP fixes
- Misc DC fixes
- Fastboot fix
- 3DLUT fixes
- GPUVM fixes
- 64bpp format fix
- Fix for MacBooks with switchable gfx
amdkfd:
- Fix possible double deletion of validate list
- Event setup fix
- Device disconnect regression fix
- APU GTT as VRAM fix
- Fix piority inversion with MQDs
- NULL check fix
radeon:
- HAINAN fix
i915/xe display:
- Regresion fix for HDR 4k displays (#15503)
- Fixup for Dell XPS 13 7390 eDP rate limit
- Memory leak fix on ACPI _DSM handling
- Add missing slice count check during DP mode validation
xe:
- drm/xe: Prevent VFs from exposing the CCS mode sysfs file
- SRIOV related fixes
- PAT cache fix
- MMIO read fix
- W/a fixes
- Adjust type of xe_modparam.force_vram_bar_size
- Wedge mode fix
- HWMon fix
* tag 'drm-next-2026-02-21' of https://gitlab.freedesktop.org/drm/kernel: (143 commits)
drm/amd/display: Remove unneeded DAC link encoder register
drm/amd/display: Enable DAC in DCE link encoder
drm/amd/display: Set CRTC source for DAC using registers
drm/amd/display: Initialize DAC in DCE link encoder using VBIOS
drm/amd/display: Turn off DAC in DCE link encoder using VBIOS
drm/amd/display: Don't call find_analog_engine() twice
drm/amdgpu: fix 4-level paging if GMC supports 57-bit VA v2
drm/amdgpu: keep vga memory on MacBooks with switchable graphics
drm/amdgpu: Set atomics to true for xgmi
drm/amdkfd: Check for NULL return values
drm/amd/display: Use same max plane scaling limits for all 64 bpp formats
drm/amdgpu: Set vmid0 PAGE_TABLE_DEPTH for GFX12.1
drm/amdkfd: Disable MQD queue priority
drm/amd/display: Remove conditional for shaper 3DLUT power-on
drm/amd/display: Check return of shaper curve to HW format
drm/amd/display: Correct logic check error for fastboot
drm/amd/display: Skip eDP detection when no sink
Revert "drm/amd/display: Add Gfx Base Case For Linear Tiling Handling"
Revert "drm/amd/display: Correct hubp GfxVersion verification"
Revert "drm/amd/display: Add Handling for gfxversion DcGfxBase"
...
ASoC: Additional Rockchip fix for v7.0
One more ASoC fix, for a regression with the Rockchip I2S TDM support on
a number of platforms.
Pull more fbdev updates from Helge Deller:
"Code cleanups for the au1100fb fbdev driver (Uwe Kleine-König)"
* tag 'fbdev-for-7.0-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
fbdev: au1100fb: Replace license boilerplate by SPDX header
fbdev: au1100fb: Fold au1100fb.h into its only user
fbdev: au1100fb: Replace custom printk wrappers by pr_*
fbdev: au1100fb: Make driver compilable on non-mips platforms
fbdev: au1100fb: Use proper conversion specifiers in printk formats
fbdev: au1100fb: Mark several local functions as static
fbdev: au1100fb: Don't store device specific data in global variables
UAPI Changes:
- drm/xe: Prevent VFs from exposing the CCS mode sysfs file (Nareshkumar)
Cross-subsystem Changes:
- drm/pagemap: pass pagemap_addr by reference (Arnd)
Driver Changes:
- SRIOV related fixes (Michal, Piotr)
- PAT cache fix (Jia)
- MMIO read fix (Shuicheng)
- W/a fixes (Roper)
- Adjust type of xe_modparam.force_vram_bar_size (Shuicheng)
- Wedge mode fix (Raag)
- HWMon fix (Karthik)
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/aZeR6CXDRbeudIVR@intel.com
ASoC: Fixes for v7.0 merge window
A reasonably small set of fixes and quriks that came in during the merge
window, there's one more pending that I'll send tomorrow if you didn't
send a PR already.
Drivers will not always call set_sysclk() for all clocks, especially when
default mclk-fs can be used.
When that is the case, use the clock rate set in the params multiplied by the
default mclk-fs.
Fixes: 5323186e2e8d ("ASoC: rockchip: i2s_tdm: Re-add the set_sysclk callback")
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Reported-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://patch.msgid.link/20260218201834.924358-1-detlev.casanova@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull tracing fixes from Steven Rostedt:
- Fix possible dereference of uninitialized pointer
When validating the persistent ring buffer on boot up, if the first
validation fails, a reference to "head_page" is performed in the
error path, but it skips over the initialization of that variable.
Move the initialization before the first validation check.
- Fix use of event length in validation of persistent ring buffer
On boot up, the persistent ring buffer is checked to see if it is
valid by several methods. One being to walk all the events in the
memory location to make sure they are all valid. The length of the
event is used to move to the next event. This length is determined by
the data in the buffer. If that length is corrupted, it could
possibly make the next event to check located at a bad memory
location.
Validate the length field of the event when doing the event walk.
- Fix function graph on archs that do not support use of ftrace_ops
When an architecture defines HAVE_DYNAMIC_FTRACE_WITH_ARGS, it means
that its function graph tracer uses the ftrace_ops of the function
tracer to call its callbacks. This allows a single registered
callback to be called directly instead of checking the callback's
meta data's hash entries against the function being traced.
For architectures that do not support this feature, it must always
call the loop function that tests each registered callback (even if
there's only one). The loop function tests each callback's meta data
against its hash of functions and will call its callback if the
function being traced is in its hash map.
The issue was that there was no check against this and the direct
function was being called even if the architecture didn't support it.
This meant that if function tracing was enabled at the same time as a
callback was registered with the function graph tracer, its callback
would be called for every function that the function tracer also
traced, even if the callback's meta data only wanted to be called
back for a small subset of functions.
Prevent the direct calling for those architectures that do not
support it.
- Fix references to trace_event_file for hist files
The hist files used event_file_data() to get a reference to the
associated trace_event_file the histogram was attached to. This would
return a pointer even if the trace_event_file is about to be freed
(via RCU). Instead it should use the event_file_file() helper that
returns NULL if the trace_event_file is marked to be freed so that no
new references are added to it.
- Wake up hist poll readers when an event is being freed
When polling on a hist file, the task is only awoken when a hist
trigger is triggered. This means that if an event is being freed
while there's a task waiting on its hist file, it will need to wait
until the hist trigger occurs to wake it up and allow the freeing to
happen. Note, the event will not be completely freed until all
references are removed, and a hist poller keeps a reference. But it
should still be woken when the event is being freed.
* tag 'trace-v7.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Wake up poll waiters for hist files when removing an event
tracing: Fix checking of freed trace_event_file for hist files
fgraph: Do not call handlers direct when not using ftrace_ops
tracing: ring-buffer: Fix to check event length before using
ring-buffer: Fix possible dereference of uninitialized pointer
This also gets rid of an old address of the FSF.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Helge Deller <deller@gmx.de>
- Add missing slice count check during DP mode validation
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patch.msgid.link/aZgb43cDcTPBYssk@jlahtine-mobl
Skip creating CCS sysfs files in VF mode to ensure VFs do not
try to change CCS mode, as it is predefined and immutable in
the SR-IOV mode.
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Nareshkumar Gollakoti <naresh.kumar.g@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patch.msgid.link/20260202170810.1393147-5-naresh.kumar.g@intel.com
(cherry picked from commit 4e8f602ac3574cf1ebc7acfb6624d06e04b30c91)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Depending on the timing during boot, the BIOS might report wrong pin
capabilities, which can lead to HDMI audio being disabled. Therefore,
force HDMI audio connection on TUXEDO InfinityBook S 14 Gen6.
Signed-off-by: Aaron Erhardt <aer@tuxedocomputers.com>
Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
Link: https://patch.msgid.link/20260218213234.429686-1-wse@tuxedocomputers.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In the original txt format binding document ak4458.txt, the supply names
are 'AVDD-supply', 'DVDD-supply', and they are also used in driver. But in
the commit converting to yaml format, they are changed to 'avdd-supply',
'dvdd-supply'. After search all the dts file, these names 'AVDD-supply',
'DVDD-supply', 'avdd-supply', 'dvdd-supply' are not used in any dts
file. So it is safe to fix the yaml binding document.
Fixes: 829d78e3ea32 ("ASoC: dt-bindings: ak5558: Convert to dtschema")
Cc: stable@vger.kernel.org
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260212021829.3244736-4-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull btrfs fixes from David Sterba:
- multiple error handling fixes of unexpected conditions
- reset block group size class once it becomes empty so that
its class can be changed
- error message level adjustments
- fixes of returned error values
- use correct block reserve for delayed refs
* tag 'for-7.0-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix invalid leaf access in btrfs_quota_enable() if ref key not found
btrfs: fix lost error return in btrfs_find_orphan_roots()
btrfs: fix lost return value on error in finish_verity()
btrfs: change unaligned root messages to error level in btrfs_validate_super()
btrfs: use the correct type to initialize block reserve for delayed refs
btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()
btrfs: reset block group size class when it becomes empty
btrfs: replace BUG() with error handling in __btrfs_balance()
btrfs: handle unexpected exact match in btrfs_set_inode_index_count()
The event_hist_poll() function attempts to verify whether an event file is
being removed, but this check may not occur or could be unnecessarily
delayed. This happens because hist_poll_wakeup() is currently invoked only
from event_hist_trigger() when a hist command is triggered. If the event
file is being removed, no associated hist command will be triggered and a
waiter will be woken up only after an unrelated hist command is triggered.
Fix the issue by adding a call to hist_poll_wakeup() in
remove_event_file_dir() after setting the EVENT_FILE_FL_FREED flag. This
ensures that a task polling on a hist file is woken up and receives
EPOLLERR.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://patch.msgid.link/20260219162737.314231-3-petr.pavlu@suse.com
Fixes: 1bd13edbbed6 ("tracing/hist: Add poll(POLLIN) support on hist file")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This gets rid of a header that is only used once. The copyrights and
license specifications are all already covered in the au1100fb.c file.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Helge Deller <deller@gmx.de>