b2aa405e89
The DRM_DP_AUX_CHARDEV and DRM_DP_CEC Kconfig symbols enable code that use DP helper functions, that are only present if CONFIG_DRM_DISPLAY_DP_HELPER is also enabled. But these don't select the DRM_DISPLAY_DP_HELPER symbol, meaning that it is possible to enable any of them without CONFIG_DRM_DISPLAY_DP_HELPER. That will lead to the following linking errors with the mentioned config: LD vmlinux.o MODPOST vmlinux.symvers MODINFO modules.builtin.modinfo GEN modules.builtin LD .tmp_vmlinux.kallsyms1 KSYMS .tmp_vmlinux.kallsyms1.S AS .tmp_vmlinux.kallsyms1.S LD .tmp_vmlinux.kallsyms2 KSYMS .tmp_vmlinux.kallsyms2.S AS .tmp_vmlinux.kallsyms2.S LD vmlinux SYSMAP System.map SORTTAB vmlinux OBJCOPY arch/arm64/boot/Image MODPOST modules-only.symvers ERROR: modpost: "drm_dp_dpcd_write" [drivers/gpu/drm/display/drm_display_helper.ko] undefined! ERROR: modpost: "drm_dp_read_desc" [drivers/gpu/drm/display/drm_display_helper.ko] undefined! ERROR: modpost: "drm_dp_dpcd_read" [drivers/gpu/drm/display/drm_display_helper.ko] undefined! make[1]: *** [scripts/Makefile.modpost:134: modules-only.symvers] Error 1 make[1]: *** Deleting file 'modules-only.symvers' make: *** [Makefile:1749: modules] Error 2 Besides making these symbols to select CONFIG_DRM_DISPLAY_DP_HELPER, make them to depend on DRM_DISPLAY_HELPER, since can't be enabled without it. Note: It seems this has been an issue for a long time but was made easier to reproduce after the commit1e0f66420b("drm/display: Introduce a DRM display-helper module"). Adding a Fixes: tag just to make sure that this fix will be picked for stable once the mentioned change also lands there. Fixes:1e0f66420b("drm/display: Introduce a DRM display-helper module") Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220428082244.390859-1-javierm@redhat.com
51 lines
1.2 KiB
Text
51 lines
1.2 KiB
Text
# SPDX-License-Identifier: MIT
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config DRM_DP_AUX_BUS
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tristate
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depends on DRM
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depends on OF
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config DRM_DISPLAY_HELPER
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tristate
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depends on DRM
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help
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DRM helpers for display adapters.
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config DRM_DISPLAY_DP_HELPER
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bool
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depends on DRM_DISPLAY_HELPER
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help
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DRM display helpers for DisplayPort.
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config DRM_DISPLAY_HDCP_HELPER
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bool
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depends on DRM_DISPLAY_HELPER
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help
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DRM display helpers for HDCP.
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config DRM_DISPLAY_HDMI_HELPER
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bool
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depends on DRM_DISPLAY_HELPER
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help
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DRM display helpers for HDMI.
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config DRM_DP_AUX_CHARDEV
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bool "DRM DP AUX Interface"
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depends on DRM && DRM_DISPLAY_HELPER
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select DRM_DISPLAY_DP_HELPER
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help
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Choose this option to enable a /dev/drm_dp_auxN node that allows to
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read and write values to arbitrary DPCD registers on the DP aux
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channel.
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config DRM_DP_CEC
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bool "Enable DisplayPort CEC-Tunneling-over-AUX HDMI support"
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depends on DRM && DRM_DISPLAY_HELPER
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select DRM_DISPLAY_DP_HELPER
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select CEC_CORE
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help
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Choose this option if you want to enable HDMI CEC support for
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DisplayPort/USB-C to HDMI adapters.
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Note: not all adapters support this feature, and even for those
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that do support this they often do not hook up the CEC pin.
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