ACK: [SRU][N][PATCH v2 0/6] Coresight fails to build on 6.8.0-102 due to missing function and arg definitions
Tim Whisonant
tim.whisonant at canonical.com
Sat Feb 28 01:27:48 UTC 2026
On Wed, Feb 25, 2026 at 08:53:56AM -0800, Noah Wager wrote:
> BugLink: https://bugs.launchpad.net/bugs/2142337
>
> SRU Justification:
>
> [Impact]
>
> When CONFIG_CORESIGHT is enabled, noble 6.8.0-102 fails to build with the following errors:
>
> ```
> drivers/hwtracing/coresight/coresight-catu.c: In function 'catu_init':
> drivers/hwtracing/coresight/coresight-catu.c:728:15: error: implicit declaration of function 'coresight_init_driver' [-Werror=implicit-function-declaration]
> 728 | ret = coresight_init_driver("catu", &catu_driver, &catu_platform_driver);
> | ^~~~~~~~~~~~~~~~~~~~~
> drivers/hwtracing/coresight/coresight-catu.c: In function 'catu_exit':
> drivers/hwtracing/coresight/coresight-catu.c:736:9: error: implicit declaration of function 'coresight_remove_driver'; did you mean 'coresight_remove_links'? [-Werror=implicit-function-declaration]
> 736 | coresight_remove_driver(&catu_driver, &catu_platform_driver);
> | ^~~~~~~~~~~~~~~~~~~~~~~
> | coresight_remove_links
> ...
> drivers/hwtracing/coresight/coresight-tmc-core.c: In function '__tmc_probe':
> drivers/hwtracing/coresight/coresight-tmc-core.c:500:65: error: 'id' undeclared (first use in this function); did you mean 'fd'?
> 500 | coresight_get_uci_data(id));
> | ^~
> | fd
> drivers/hwtracing/coresight/coresight-tmc-core.c:500:65: note: each undeclared identifier is reported only once for each function it appears in
> ...
> drivers/hwtracing/coresight/coresight-tmc-core.c: In function 'tmc_init':
> drivers/hwtracing/coresight/coresight-tmc-core.c:728:16: error: implicit declaration of function 'coresight_init_driver' [-Werror=implicit-function-declaration]
> 728 | return coresight_init_driver("tmc", &tmc_driver, &tmc_platform_driver);
> | ^~~~~~~~~~~~~~~~~~~~~
> drivers/hwtracing/coresight/coresight-tmc-core.c: In function 'tmc_exit':
> drivers/hwtracing/coresight/coresight-tmc-core.c:733:9: error: implicit declaration of function 'coresight_remove_driver'; did you mean 'coresight_remove_links'? [-Werror=implicit-function-declaration]
> 733 | coresight_remove_driver(&tmc_driver, &tmc_platform_driver);
> | ^~~~~~~~~~~~~~~~~~~~~~~
> | coresight_remove_links
> ...
> drivers/hwtracing/coresight/coresight-tpdm.c: In function 'tpdm_enable':
> drivers/hwtracing/coresight/coresight-tpdm.c:299:14: error: implicit declaration of function 'coresight_take_mode'; did you mean 'coresight_make_links'? [-Werror=implicit-function-declaration]
> 299 | if (!coresight_take_mode(csdev, mode)) {
> | ^~~~~~~~~~~~~~~~~~~
> | coresight_make_links
> drivers/hwtracing/coresight/coresight-tpdm.c: In function 'tpdm_disable':
> drivers/hwtracing/coresight/coresight-tpdm.c:345:9: error: implicit declaration of function 'coresight_set_mode'; did you mean 'coresight_get_pid'? [-Werror=implicit-function-declaration]
> 345 | coresight_set_mode(csdev, CS_MODE_DISABLED);
> | ^~~~~~~~~~~~~~~~~~
> | coresight_get_pid
> drivers/hwtracing/coresight/coresight-dummy.c: In function 'dummy_source_enable':
> drivers/hwtracing/coresight/coresight-dummy.c:26:14: error: implicit declaration of function 'coresight_take_mode'; did you mean 'coresight_make_links'? [-Werror=implicit-function-declaration]
> 26 | if (!coresight_take_mode(csdev, mode))
> | ^~~~~~~~~~~~~~~~~~~
> | coresight_make_links
> drivers/hwtracing/coresight/coresight-dummy.c: In function 'dummy_source_disable':
> drivers/hwtracing/coresight/coresight-dummy.c:37:9: error: implicit declaration of function 'coresight_set_mode'; did you mean 'coresight_get_pid'? [-Werror=implicit-function-declaration]
> 37 | coresight_set_mode(csdev, CS_MODE_DISABLED);
> | ^~~~~~~~~~~~~~~~~~
> | coresight_get_pid
> ```
>
> These errors are a result of including the following patches in upstream stable updates, but missing some dependencies from the original patch sets:
>
> Error description: __tmc_probe:id not defined
> Break commit: n/linux aaf260b9572e ("coresight: tmc: Move ACPI support from AMBA driver to platform driver")
> Missing commit: 852e9a32058a ("coresight: stm: Extract device name from AMBA pid based table lookup")
> 3ab210297c31 ("coresight: tmc: Extract device properties from AMBA pid based table lookup")
> Patch series: "coresight: Move remaining AMBA ACPI devices into platform driver"
> (https://lists-ec2.linaro.org/archives/list/coresight@lists.linaro.org/thread/XGJAJMHSDE5P7YSX33CIW5DHKR6C343L/)
>
> Error description: catu,tmc: coresight_{init,remove}_driver not defined
> Break commit: n/linux aaf260b9572e ("coresight: tmc: Move ACPI support from AMBA driver to platform driver")
> n/linux cf08211db65c ("coresight: catu: Move ACPI support from AMBA driver to platform driver")
> Missing commit: 075b7cd7ad7d ("coresight: Add helpers registering/removing both AMBA and platform drivers")
> Patch series: "coresight: Move remaining AMBA ACPI devices into platform driver"
> (https://lists-ec2.linaro.org/archives/list/coresight@lists.linaro.org/thread/XGJAJMHSDE5P7YSX33CIW5DHKR6C343L/)
>
> Error description: tpdm,dummy: coresight_{set,take}_mode not defined
> Break commit: n/linux f30974e15e66 ("Coresight: Set correct cs_mode for TPDM to fix disable issue")
> n/linux e76e67682488 ("Coresight: Set correct cs_mode for dummy source to fix disable issue")
> Missing commit: d724f65218b9 ("coresight: Add helper for atomically taking the device")
> Patch series: "coresight: Separate sysfs and Perf usage and some other cleanups"
> (https://lists.infradead.org/pipermail/linux-arm-kernel/2024-January/899269.html)
>
> [Fix]
>
> Revert the break commits.
>
> [Test Plan]
>
> Ensure CONFIG_CORESIGHT and CONFIG_CORESIGHT_CATU are enabled, then compile test.
>
> [Where problems could occur]
>
> These reverts are technically removing fixes from the tree, which have the
> potential to cause behaviour changes or regressions. However, the generic
> kernel has never been able to build these coresight features, and thus we have
> not observed any examples of the issue the patches intended to fix.
>
> Noah Wager (6):
> UBUNTU: SAUCE: Revert "coresight: catu: Support atclk"
> UBUNTU: SAUCE: Revert "coresight: catu: Move ACPI support from AMBA
> driver to platform driver"
> UBUNTU: SAUCE: Revert "coresight: tmc: Support atclk"
> UBUNTU: SAUCE: Revert "coresight: tmc: Move ACPI support from AMBA
> driver to platform driver"
> UBUNTU: SAUCE: Revert "Coresight: Set correct cs_mode for TPDM to fix
> disable issue"
> UBUNTU: SAUCE: Revert "Coresight: Set correct cs_mode for dummy source
> to fix disable issue"
>
> drivers/acpi/arm64/amba.c | 3 +
> drivers/hwtracing/coresight/coresight-catu.c | 150 +++--------------
> drivers/hwtracing/coresight/coresight-catu.h | 2 -
> drivers/hwtracing/coresight/coresight-dummy.c | 4 -
> .../hwtracing/coresight/coresight-tmc-core.c | 152 ++----------------
> drivers/hwtracing/coresight/coresight-tmc.h | 4 -
> drivers/hwtracing/coresight/coresight-tpdm.c | 6 -
> 7 files changed, 37 insertions(+), 284 deletions(-)
>
> --
> 2.43.0
>
>
Acked-by: Tim Whisonant <tim.whisonant at canonical.com>
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