Messages in this thread | | | From | Randy Dunlap <> | Subject | Re: gpu: drm_fb_cma_helper.c:46: undefined reference to `drm_gem_fb_get_obj' | Date | Tue, 26 Oct 2021 17:58:34 -0700 |
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On 10/26/21 11:21 AM, Thomas Zimmermann wrote: > Hi > > Am 25.10.21 um 14:13 schrieb Naresh Kamboju: >> Regression found on arm gcc-11 built with multi_v5_defconfig >> Following build warnings / errors reported on linux next 20211025. >> >> metadata: >> git_describe: next-20211025 >> git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next >> git_short_log: 9ae1fbdeabd3 (\"Add linux-next specific files for 20211025\") >> target_arch: arm >> toolchain: gcc-11 >> config: multi_v5_defconfig >> >> build error : >> -------------- >> arm-linux-gnueabihf-ld: drivers/gpu/drm/drm_fb_cma_helper.o: in >> function `drm_fb_cma_get_gem_obj': >> drivers/gpu/drm/drm_fb_cma_helper.c:46: undefined reference to >> `drm_gem_fb_get_obj' >> arm-linux-gnueabihf-ld: drivers/gpu/drm/drm_fb_cma_helper.c:46: >> undefined reference to `drm_gem_fb_get_obj' >> arm-linux-gnueabihf-ld: drivers/gpu/drm/drm_fb_cma_helper.c:46: >> undefined reference to `drm_gem_fb_get_obj' >> arm-linux-gnueabihf-ld: drivers/gpu/drm/drm_fb_cma_helper.o: in >> function `drm_fb_cma_sync_non_coherent': >> drivers/gpu/drm/drm_fb_cma_helper.c:133: undefined reference to >> `drm_atomic_helper_damage_iter_init' >> arm-linux-gnueabihf-ld: drivers/gpu/drm/drm_fb_cma_helper.c:135: >> undefined reference to `drm_atomic_helper_damage_iter_next' >> make[1]: *** [Makefile:1252: vmlinux] Error 1 >> make[1]: Target '__all' not remade because of errors. >> make: *** [Makefile:226: __sub-make] Error 2 >> >> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org> >> >> >> build link: >> ----------- >> https://builds.tuxbuild.com/1zzgFZBGjpQ5R0lawQFW9iJ39Hp/build.log >> >> build config: >> ------------- >> https://builds.tuxbuild.com/1zzgFZBGjpQ5R0lawQFW9iJ39Hp/config > > Looking at this config, there is: > > CONFIG_DRM=y > # CONFIG_DRM_DP_AUX_CHARDEV is not set > # CONFIG_DRM_DEBUG_MM is not set > # CONFIG_DRM_DEBUG_SELFTEST is not set > CONFIG_DRM_KMS_HELPER=m > # CONFIG_DRM_LOAD_EDID_FIRMWARE is not set > # CONFIG_DRM_DP_CEC is not set > CONFIG_DRM_GEM_CMA_HELPER=y > CONFIG_DRM_KMS_CMA_HELPER=y > > GEM_CMA_HELPER depends on KMS_HELPER, but the latter is a module. That's probably the cause of the problem. Is it intentionally set this way? >
The only drivers that select DRM_KMS_HELPER are both =m, so that's how DRM_KMS_HELPER is set also.
Symbol: DRM_KMS_HELPER [=m] Type : tristate Defined at drivers/gpu/drm/Kconfig:82 Depends on: HAS_IOMEM [=y] && DRM [=y] Selected by [m]: - DRM_ATMEL_HLCDC [=m] && HAS_IOMEM [=y] && DRM [=y] && OF [=y] && COMMON_CLK [=y] && MFD_ATMEL_HLCDC [=y] && ARM [=y] - DRM_ASPEED_GFX [=m] && HAS_IOMEM [=y] && DRM [=y] && OF [=y] && (COMPILE_TEST [=n] || ARCH_ASPEED [=y]) && MMU [=y]
I did the ARM cross-build and also see the linker error. I didn't understand why -- and still don't, but here is a little speculation:
In the past (e.g. 10 years ago), we have to move some .o files in lib/ from lib-y to obj-y so that they would always be included in the final object file and not cause their user/caller object files to suffer from undefined references. These happened because unused functions(?) in lib-y files are stripped out of the final object files. The same thing could be happening here (still just guessing).
Does that help any? I dunno.
Adding Arnd to Cc: to see if he has any ideas...
>> >> # To install tuxmake on your system globally >> # sudo pip3 install -U tuxmake >> tuxmake --runtime podman --target-arch arm --toolchain gcc-11 >> --kconfig multi_v5_defconfig >> >> -- >> Linaro LKFT >> https://lkft.linaro.org
-- ~Randy
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