From: Maxime Ripard maxime@cerno.tech
[ Upstream commit d1c0b7de4dfa5505cf7a1d6220aa72aace4435d0 ]
The VC4 HDMI controller driver relies on the HDMI codec ASoC driver. In order to set it up properly, in vc4_hdmi_audio_init(), our HDMI driver will register a device matching the HDMI codec driver, and then register an ASoC card using that codec.
However, if vc4 is compiled as a module, chances are that the hdmi-codec driver will be too. In such a case, the module loader will have a very narrow window to load the module between the device registration and the card registration.
If it fails to load the module in time, the card registration will fail with EPROBE_DEFER, and we'll abort the audio initialisation, unregistering the HDMI codec device in the process.
The next time the bind callback will be run, it's likely that we end up missing that window again, effectively preventing vc4 to probe entirely.
In order to prevent this, we can create a soft dependency of the vc4 driver on the HDMI codec one so that we're sure the HDMI codec will be loaded before the VC4 module is, and thus we'll never end up in the previous situation.
Fixes: 91e99e113929 ("drm/vc4: hdmi: Register HDMI codec") Reviewed-by: Javier Martinez Canillas javierm@redhat.com Signed-off-by: Maxime Ripard maxime@cerno.tech Link: https://patchwork.freedesktop.org/patch/msgid/20220902144111.3424560-1-maxim... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/vc4/vc4_drv.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c index 6b8dfa1e7650..c186ace7f83b 100644 --- a/drivers/gpu/drm/vc4/vc4_drv.c +++ b/drivers/gpu/drm/vc4/vc4_drv.c @@ -490,6 +490,7 @@ module_init(vc4_drm_register); module_exit(vc4_drm_unregister);
MODULE_ALIAS("platform:vc4-drm"); +MODULE_SOFTDEP("pre: snd-soc-hdmi-codec"); MODULE_DESCRIPTION("Broadcom VC4 DRM Driver"); MODULE_AUTHOR("Eric Anholt eric@anholt.net"); MODULE_LICENSE("GPL v2");