From 36af2d5c4433fb40ee2af912c4ac0a30991aecfc Mon Sep 17 00:00:00 2001
From: Kai-Heng Feng <kai.heng.feng@canonical.com>
Date: Fri, 22 Jan 2021 20:53:02 +0800
Subject: [PATCH] ACPI: sysfs: Prefer "compatible" modalias
Git-commit: 36af2d5c4433fb40ee2af912c4ac0a30991aecfc
Patch-mainline: v5.11-rc6
References: git-fixes

Commit 8765c5ba1949 ("ACPI / scan: Rework modalias creation when
"compatible" is present") may create two "MODALIAS=" in one uevent
file if specific conditions are met.

This breaks systemd-udevd, which assumes each "key" in one uevent file
to be unique. The internal implementation of systemd-udevd overwrites
the first MODALIAS with the second one, so its kmod rule doesn't load
the driver for the first MODALIAS.

So if both the ACPI modalias and the OF modalias are present, use the
latter to ensure that there will be only one MODALIAS.

Link: https://github.com/systemd/systemd/pull/18163
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: 4.1+ <stable@vger.kernel.org> # 4.1+
[ rjw: Subject and changelog edits ]

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/acpi/device_sysfs.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index 96869f1538b9..bfca116482b8 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -251,20 +251,12 @@ int __acpi_device_uevent_modalias(struct acpi_device *adev,
 	if (add_uevent_var(env, "MODALIAS="))
 		return -ENOMEM;
 
-	len = create_pnp_modalias(adev, &env->buf[env->buflen - 1],
-				  sizeof(env->buf) - env->buflen);
-	if (len < 0)
-		return len;
-
-	env->buflen += len;
-	if (!adev->data.of_compatible)
-		return 0;
-
-	if (len > 0 && add_uevent_var(env, "MODALIAS="))
-		return -ENOMEM;
-
-	len = create_of_modalias(adev, &env->buf[env->buflen - 1],
-				 sizeof(env->buf) - env->buflen);
+	if (adev->data.of_compatible)
+		len = create_of_modalias(adev, &env->buf[env->buflen - 1],
+					 sizeof(env->buf) - env->buflen);
+	else
+		len = create_pnp_modalias(adev, &env->buf[env->buflen - 1],
+					  sizeof(env->buf) - env->buflen);
 	if (len < 0)
 		return len;
 
-- 
2.26.2