linux-kernel - [PATCH v3] platform/x86: thinkpad_acpi: disable ACPI fan access for T495* and E560

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Message-ID: <20250324152442.106113-1-ImanDevel@gmail.com>
Date: Mon, 24 Mar 2025 11:24:42 -0400
From: Seyediman Seyedarab <imandevel@...il.com>
To: hmh@....eng.br,
	hdegoede@...hat.com,
	ilpo.jarvinen@...ux.intel.com
Cc: ibm-acpi-devel@...ts.sourceforge.net,
	platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Seyediman Seyedarab <ImanDevel@...il.com>,
	Vlastimil Holer <vlastimil.holer@...il.com>,
	stable@...r.kernel.org,
	Alireza Elikahi <scr0lll0ck1s4b0v3h0m3k3y@...il.com>,
	Kurt Borja <kuurtb@...il.com>,
	Eduard Christian Dumitrescu <eduard.c.dumitrescu@...il.com>
Subject: [PATCH v3] platform/x86: thinkpad_acpi: disable ACPI fan access for T495* and E560

From: Eduard Christian Dumitrescu <eduard.c.dumitrescu@...il.com>

T495, T495s, and E560 laptops have the FANG+FANW ACPI methods (therefore
fang_handle and fanw_handle are not NULL) but they do not actually work,
which results in a "No such device or address" error. The DSDT table code
for the FANG+FANW methods doesn't seem to do anything special regarding
the fan being secondary. Fan access and control is restored after forcing
the legacy non-ACPI fan control method by setting both fang_handle and
fanw_handle to NULL. The bug was introduced in commit 57d0557dfa49
("platform/x86: thinkpad_acpi: Add Thinkpad Edge E531 fan support"),
which added a new fan control method via the FANG+FANW ACPI methods.

Add a quirk for T495, T495s, and E560 to avoid the FANG+FANW methods.

Reported-by: Vlastimil Holer <vlastimil.holer@...il.com>
Fixes: 57d0557dfa49 ("platform/x86: thinkpad_acpi: Add Thinkpad Edge E531 fan support")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219643
Cc: stable@...r.kernel.org
Tested-by: Alireza Elikahi <scr0lll0ck1s4b0v3h0m3k3y@...il.com>
Reviewed-by: Kurt Borja <kuurtb@...il.com>
Signed-off-by: Eduard Christian Dumitrescu <eduard.c.dumitrescu@...il.com>
Co-developed-by: Seyediman Seyedarab <ImanDevel@...il.com>
Signed-off-by: Seyediman Seyedarab <ImanDevel@...il.com>
---
Changes in v3:
- Reordered paragraphs in the changelog and made minor adjusments
- Reorded tags
- Added Kurt Borja as a reviewer
- Removed Tested-by: crok <crok.bic@...il.com> as crok didn't test
  the patch

Kindest Regards,
Seyediman

 drivers/platform/x86/thinkpad_acpi.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index d8df1405edfa..27fd67a2f2d1 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -8793,6 +8793,7 @@ static const struct attribute_group fan_driver_attr_group = {
 #define TPACPI_FAN_NS		0x0010		/* For EC with non-Standard register addresses */
 #define TPACPI_FAN_DECRPM	0x0020		/* For ECFW's with RPM in register as decimal */
 #define TPACPI_FAN_TPR		0x0040		/* Fan speed is in Ticks Per Revolution */
+#define TPACPI_FAN_NOACPI	0x0080		/* Don't use ACPI methods even if detected */
 
 static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
 	TPACPI_QEC_IBM('1', 'Y', TPACPI_FAN_Q1),
@@ -8823,6 +8824,9 @@ static const struct tpacpi_quirk fan_quirk_table[] __initconst = {
 	TPACPI_Q_LNV3('N', '1', 'O', TPACPI_FAN_NOFAN),	/* X1 Tablet (2nd gen) */
 	TPACPI_Q_LNV3('R', '0', 'Q', TPACPI_FAN_DECRPM),/* L480 */
 	TPACPI_Q_LNV('8', 'F', TPACPI_FAN_TPR),		/* ThinkPad x120e */
+	TPACPI_Q_LNV3('R', '0', '0', TPACPI_FAN_NOACPI),/* E560 */
+	TPACPI_Q_LNV3('R', '1', '2', TPACPI_FAN_NOACPI),/* T495 */
+	TPACPI_Q_LNV3('R', '1', '3', TPACPI_FAN_NOACPI),/* T495s */
 };
 
 static int __init fan_init(struct ibm_init_struct *iibm)
@@ -8874,6 +8878,13 @@ static int __init fan_init(struct ibm_init_struct *iibm)
 		tp_features.fan_ctrl_status_undef = 1;
 	}
 
+	if (quirks & TPACPI_FAN_NOACPI) {
+		/* E560, T495, T495s */
+		pr_info("Ignoring buggy ACPI fan access method\n");
+		fang_handle = NULL;
+		fanw_handle = NULL;
+	}
+
 	if (gfan_handle) {
 		/* 570, 600e/x, 770e, 770x */
 		fan_status_access_mode = TPACPI_FAN_RD_ACPI_GFAN;
-- 
2.48.1