Messages in this thread | | | Date | Thu, 28 Apr 2022 09:02:32 +0200 | Subject | Re: [PATCH v2] drm/display: Select DP helper for DRM_DP_AUX_CHARDEV and DRM_DP_CEC | From | Thomas Zimmermann <> |
| |
Hi
Am 27.04.22 um 23:55 schrieb Javier Martinez Canillas: > 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 > > Note: It seems this has been an issue for a long time but was made easier > to reproduce after the commit 1e0f66420b13 ("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: 1e0f66420b13 ("drm/display: Introduce a DRM display-helper module") > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > --- > > Changes in v2: > - Explain better the issue in the change description. > - Only select DRM_DISPLAY_DP_HELPER and not DRM_DISPLAY_HELPER. > > drivers/gpu/drm/display/Kconfig | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/display/Kconfig b/drivers/gpu/drm/display/Kconfig > index f84f1b0cd23f..9fe80c4e555c 100644 > --- a/drivers/gpu/drm/display/Kconfig > +++ b/drivers/gpu/drm/display/Kconfig > @@ -32,6 +32,7 @@ config DRM_DISPLAY_HDMI_HELPER > config DRM_DP_AUX_CHARDEV > bool "DRM DP AUX Interface" > depends on DRM > + select DRM_DISPLAY_DP_HELPER
You cannot select DISPLAY_DP_HELPER without DISPLAY_HELPER.
Can't you simply make it depend on DISPLAY_DP_HELPER. The menu entry will show up as soon as there's a driver that selcets DISPLAY_DP_HELPER.
Best regards Thomas
> help > Choose this option to enable a /dev/drm_dp_auxN node that allows to > read and write values to arbitrary DPCD registers on the DP aux > @@ -40,6 +41,7 @@ config DRM_DP_AUX_CHARDEV > config DRM_DP_CEC > bool "Enable DisplayPort CEC-Tunneling-over-AUX HDMI support" > depends on DRM > + select DRM_DISPLAY_DP_HELPER > select CEC_CORE > help > Choose this option if you want to enable HDMI CEC support for
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev [unhandled content-type:application/pgp-signature] | |