[PATCH i-g-t 2/4] tests/core_hotunplug: Also unload audio on device unplug

[Janusz Krzysztofik]

Starting from commit e9c69e02b2f7 ("tests/core_hotunplug: Unload snd
driver before i915 unbind") that replaced a former conservative workaround
with a more liberal one but also moved it out of initial igt_fixture
section to driver_unbind(), *plug* subtests (still blockisted in CI) can
suffer from issues related to an audio driver using i915 hardware.  Fix it
by adding a copy of the workaround in its current shape also to
device_unplug() / bus_rescan() pair of functions.

Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
---
 tests/core_hotunplug.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tests/core_hotunplug.c b/tests/core_hotunplug.c
index 9961cdad57..669b8ce1bc 100644
--- a/tests/core_hotunplug.c
+++ b/tests/core_hotunplug.c
@@ -198,6 +198,21 @@ static void device_unplug(struct hotunplug *priv, const char *prefix,
 {
 	igt_require(priv->fd.sysfs_dev == -1);
 
+	/*
+	 * FIXME: on some devices, the audio driver (snd_hda_intel)
+	 * binds into the i915 driver. On such hardware, kernel warnings
+	 * and errors may happen if i915 is unbind/removed before removing
+	 * first the audio driver.
+	 * So, add a logic that unloads the audio driver before trying to
+	 * unbind i915 driver, reloading it when binding again.
+	 */
+	if (igt_audio_driver_unload(&priv->snd_driver)) {
+		igt_skip("Audio driver %s in use, skipping test\n",
+			 priv->snd_driver);
+	} else if (priv->snd_driver) {
+		igt_info("Unloaded audio driver %s\n", priv->snd_driver);
+	}
+
 	priv->fd.sysfs_dev = openat(priv->fd.sysfs_bus, priv->dev_bus_addr,
 				    O_DIRECTORY);
 	igt_assert_fd(priv->fd.sysfs_dev);
@@ -231,6 +246,13 @@ static void bus_rescan(struct hotunplug *priv, int timeout)
 	igt_fail_on_f(faccessat(priv->fd.sysfs_bus, priv->dev_bus_addr,
 				F_OK, 0),
 		      "Fakely unplugged device not rediscovered (%s)!\n", priv->dev_bus_addr);
+
+	if (priv->snd_driver) {
+		igt_info("Realoading %s\n", priv->snd_driver);
+		igt_kmod_load(priv->snd_driver, NULL);
+		kfree(priv->snd_driver);
+		priv->snd_driver = NULL;
+	}
 }
 
 static void cleanup(struct hotunplug *priv)
-- 
2.25.1