From d1c0b7de4dfa5505cf7a1d6220aa72aace4435d0 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Fri, 2 Sep 2022 16:41:11 +0200
Subject: [PATCH] drm/vc4: Add module dependency on hdmi-codec
Git-commit: d1c0b7de4dfa5505cf7a1d6220aa72aace4435d0
Patch-mainline: v6.1-rc2
References: git-fixes

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-maxime@cerno.tech
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 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 292d1b6a01b6..3dc01af0f90f 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -480,6 +480,7 @@ 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");
-- 
2.43.0