Commit 963e22c0 authored by Armin Wolf's avatar Armin Wolf Committed by Rafael J. Wysocki
Browse files

ACPI: EC: Relax sanity check of the ECDT ID string 



It turns out that the ECDT table inside the ThinkBook 14 G7 IML
contains a valid EC description but an invalid ID string
("_SB.PC00.LPCB.EC0"). Ignoring this ECDT based on the invalid
ID string prevents the kernel from detecting the built-in touchpad,
so relax the sanity check of the ID string and only reject ECDTs
with empty ID strings.

Reported-by: default avatarIlya K <me@0upti.me>
Fixes: 7a0d59f6 ("ACPI: EC: Ignore ECDT tables with an invalid ID string")
Signed-off-by: default avatarArmin Wolf <W_Armin@gmx.de>
Tested-by: default avatarIlya K <me@0upti.me>
Link: https://patch.msgid.link/20250729062038.303734-1-W_Armin@gmx.de


Cc: 6.16+ <stable@vger.kernel.org> # 6.16+
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 8f5ae30d

drivers/acpi/ec.c

+7 −3
Original line number Diff line number Diff line
@@ -2033,7 +2033,7 @@ void __init acpi_ec_ecdt_probe(void) 
		goto out;

	}



	if (!strstarts(ecdt_ptr->id, "\\")) {

	if (!strlen(ecdt_ptr->id)) {

		/*

		 * The ECDT table on some MSI notebooks contains invalid data, together

		 * with an empty ID string ("").
@@ -2042,9 +2042,13 @@ void __init acpi_ec_ecdt_probe(void) 
		 * a "fully qualified reference to the (...) embedded controller device",

		 * so this string always has to start with a backslash.

		 *

		 * By verifying this we can avoid such faulty ECDT tables in a safe way.

		 * However some ThinkBook machines have a ECDT table with a valid EC

		 * description but an invalid ID string ("_SB.PC00.LPCB.EC0").

		 *

		 * Because of this we only check if the ID string is empty in order to

		 * avoid the obvious cases.

		 */

		pr_err(FW_BUG "Ignoring ECDT due to invalid ID string \"%s\"\n", ecdt_ptr->id);

		pr_err(FW_BUG "Ignoring ECDT due to empty ID string\n");

		goto out;

	}