linux-kernel - [PATCH] platform/x86: thinkpad_acpi: Only update profile if successfully converted

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Date: Fri, 16 Feb 2024 20:23:11 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: Hans de Goede <hdegoede@...hat.com>, Mark Pearson
	<mpearson-lenovo@...ebb.ca>
CC: <platform-driver-x86@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH] platform/x86: thinkpad_acpi: Only update profile if successfully converted

Randomly a Lenovo Z13 will trigger a kernel warning traceback from this
condition:

```
if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
```

This happens because thinkpad-acpi always assumes that
convert_dytc_to_profile() successfully updated the profile. On the
contrary a condition can occur that when dytc_profile_refresh() is called
the profile doesn't get updated as there is a -EOPNOTSUPP branch.

Catch this situation and avoid updating the profile. Also log this into
dynamic debugging in case any other modes should be added in the future.

Fixes: c3bfcd4c6762 ("platform/x86: thinkpad_acpi: Add platform profile support")
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
BTW - This isn't new.  I've been seeing this a long time, but I just finally
got annoyed enough by it to find the code that triggered the sequence.

 drivers/platform/x86/thinkpad_acpi.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index c4895e9bc714..5ecd9d33250d 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -10308,6 +10308,7 @@ static int convert_dytc_to_profile(int funcmode, int dytcmode,
 		return 0;
 	default:
 		/* Unknown function */
+		pr_debug("unknown function 0x%x\n", funcmode);
 		return -EOPNOTSUPP;
 	}
 	return 0;
@@ -10493,8 +10494,8 @@ static void dytc_profile_refresh(void)
 		return;
 
 	perfmode = (output >> DYTC_GET_MODE_BIT) & 0xF;
-	convert_dytc_to_profile(funcmode, perfmode, &profile);
-	if (profile != dytc_current_profile) {
+	err = convert_dytc_to_profile(funcmode, perfmode, &profile);
+	if (!err && profile != dytc_current_profile) {
 		dytc_current_profile = profile;
 		platform_profile_notify();
 	}
-- 
2.34.1