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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
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Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ...
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+.. SPDX-License-Identifier: (GPL-2.0+ OR CC-BY-4.0)
+.. [see the bottom of this file for redistribution information]
+
+======================
+Bisecting a regression
+======================
+
+This document describes how to use a ``git bisect`` to find the source code
+change that broke something -- for example when some functionality stopped
+working after upgrading from Linux 6.0 to 6.1.
+
+The text focuses on the gist of the process. If you are new to bisecting the
+kernel, better follow Documentation/admin-guide/verify-bugs-and-bisect-regressions.rst
+instead: it depicts everything from start to finish while covering multiple
+aspects even kernel developers occasionally forget. This includes detecting
+situations early where a bisection would be a waste of time, as nobody would
+care about the result -- for example, because the problem happens after the
+kernel marked itself as 'tainted', occurs in an abandoned version, was already
+fixed, or is caused by a .config change you or your Linux distributor performed.
+
+Finding the change causing a kernel issue using a bisection
+===========================================================
+
+*Note: the following process assumes you prepared everything for a bisection.
+This includes having a Git clone with the appropriate sources, installing the
+software required to build and install kernels, as well as a .config file stored
+in a safe place (the following example assumes '~/prepared_kernel_.config') to
+use as pristine base at each bisection step; ideally, you have also worked out
+a fully reliable and straight-forward way to reproduce the regression, too.*
+
+* Preparation: start the bisection and tell Git about the points in the history
+ you consider to be working and broken, which Git calls 'good' and 'bad'::
+
+ git bisect start
+ git bisect good v6.0
+ git bisect bad v6.1
+
+ Instead of Git tags like 'v6.0' and 'v6.1' you can specify commit-ids, too.
+
+1. Copy your prepared .config into the build directory and adjust it to the
+ needs of the codebase Git checked out for testing::
+
+ cp ~/prepared_kernel_.config .config
+ make olddefconfig
+
+2. Now build, install, and boot a kernel. This might fail for unrelated reasons,
+ for example, when a compile error happens at the current stage of the
+ bisection a later change resolves. In such cases run ``git bisect skip`` and
+ go back to step 1.
+
+3. Check if the functionality that regressed works in the kernel you just built.
+
+ If it works, execute::
+
+ git bisect good
+
+ If it is broken, run::
+
+ git bisect bad
+
+ Note, getting this wrong just once will send the rest of the bisection
+ totally off course. To prevent having to start anew later you thus want to
+ ensure what you tell Git is correct; it is thus often wise to spend a few
+ minutes more on testing in case your reproducer is unreliable.
+
+ After issuing one of these two commands, Git will usually check out another
+ bisection point and print something like 'Bisecting: 675 revisions left to
+ test after this (roughly 10 steps)'. In that case go back to step 1.
+
+ If Git instead prints something like 'cafecaca0c0dacafecaca0c0dacafecaca0c0da
+ is the first bad commit', then you have finished the bisection. In that case
+ move to the next point below. Note, right after displaying that line Git will
+ show some details about the culprit including its patch description; this can
+ easily fill your terminal, so you might need to scroll up to see the message
+ mentioning the culprit's commit-id.
+
+ In case you missed Git's output, you can always run ``git bisect log`` to
+ print the status: it will show how many steps remain or mention the result of
+ the bisection.
+
+* Recommended complementary task: put the bisection log and the current .config
+ file aside for the bug report; furthermore tell Git to reset the sources to
+ the state before the bisection::
+
+ git bisect log > ~/bisection-log
+ cp .config ~/bisection-config-culprit
+ git bisect reset
+
+* Recommended optional task: try reverting the culprit on top of the latest
+ codebase and check if that fixes your bug; if that is the case, it validates
+ the bisection and enables developers to resolve the regression through a
+ revert.
+
+ To try this, update your clone and check out latest mainline. Then tell Git
+ to revert the change by specifying its commit-id::
+
+ git revert --no-edit cafec0cacaca0
+
+ Git might reject this, for example when the bisection landed on a merge
+ commit. In that case, abandon the attempt. Do the same, if Git fails to revert
+ the culprit on its own because later changes depend on it -- at least unless
+ you bisected a stable or longterm kernel series, in which case you want to
+ check out its latest codebase and try a revert there.
+
+ If a revert succeeds, build and test another kernel to check if reverting
+ resolved your regression.
+
+With that the process is complete. Now report the regression as described by
+Documentation/admin-guide/reporting-issues.rst.
+
+Bisecting linux-next
+--------------------
+
+If you face a problem only happening in linux-next, bisect between the
+linux-next branches 'stable' and 'master'. The following commands will start
+the process for a linux-next tree you added as a remote called 'next'::
+
+ git bisect start
+ git bisect good next/stable
+ git bisect bad next/master
+
+The 'stable' branch refers to the state of linux-mainline that the current
+linux-next release (found in the 'master' branch) is based on -- the former
+thus should be free of any problems that show up in -next, but not in Linus'
+tree.
+
+This will bisect across a wide range of changes, some of which you might have
+used in earlier linux-next releases without problems. Sadly there is no simple
+way to avoid checking them: bisecting from one linux-next release to a later
+one (say between 'next-20241020' and 'next-20241021') is impossible, as they
+share no common history.
+
+Additional reading material
+---------------------------
+
+* The `man page for 'git bisect' <https://git-scm.com/docs/git-bisect>`_ and
+ `fighting regressions with 'git bisect' <https://git-scm.com/docs/git-bisect-lk2009.html>`_
+ in the Git documentation.
+* `Working with git bisect <https://nathanchance.dev/posts/working-with-git-bisect/>`_
+ from kernel developer Nathan Chancellor.
+* `Using Git bisect to figure out when brokenness was introduced <http://webchick.net/node/99>`_.
+* `Fully automated bisecting with 'git bisect run' <https://lwn.net/Articles/317154>`_.
+
+..
+ end-of-content
+..
+ This document is maintained by Thorsten Leemhuis <linux@leemhuis.info>. If
+ you spot a typo or small mistake, feel free to let him know directly and
+ he'll fix it. You are free to do the same in a mostly informal way if you
+ want to contribute changes to the text -- but for copyright reasons please CC
+ linux-doc@vger.kernel.org and 'sign-off' your contribution as
+ Documentation/process/submitting-patches.rst explains in the section 'Sign
+ your work - the Developer's Certificate of Origin'.
+..
+ This text is available under GPL-2.0+ or CC-BY-4.0, as stated at the top
+ of the file. If you want to distribute this text under CC-BY-4.0 only,
+ please use 'The Linux kernel development community' for author attribution
+ and link this as source:
+ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/Documentation/admin-guide/bug-bisect.rst
+
+..
+ Note: Only the content of this RST file as found in the Linux kernel sources
+ is available under CC-BY-4.0, as versions of this text that were processed
+ (for example by the kernel's build system) might contain content taken from
+ files which use a more restrictive license.