diff options
| author | Hui Wang <hui.wang@canonical.com> | 2020-12-11 10:18:14 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-12-29 13:42:42 +0100 |
| commit | 51d347d7a501f81f231784ba37ba1dc5bed33a39 (patch) | |
| tree | 9f316cb52d050666626b768ce1ee184ce53599b4 /drivers/acpi | |
| parent | c30a0bd80e286d89d8dc8d164f8f10343c92c806 (diff) | |
ACPI: PNP: compare the string length in the matching_id()
commit b08221c40febcbda9309dd70c61cf1b0ebb0e351 upstream.
Recently we met a touchscreen problem on some Thinkpad machines, the
touchscreen driver (i2c-hid) is not loaded and the touchscreen can't
work.
An i2c ACPI device with the name WACF2200 is defined in the BIOS, with
the current rule in matching_id(), this device will be regarded as
a PNP device since there is WACFXXX in the acpi_pnp_device_ids[] and
this PNP device is attached to the acpi device as the 1st
physical_node, this will make the i2c bus match fail when i2c bus
calls acpi_companion_match() to match the acpi_id_table in the i2c-hid
driver.
WACF2200 is an i2c device instead of a PNP device, after adding the
string length comparing, the matching_id() will return false when
matching WACF2200 and WACFXXX, and it is reasonable to compare the
string length when matching two IDs.
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/acpi_pnp.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_pnp.c b/drivers/acpi/acpi_pnp.c index 48fc3ad13a4b..1738eb0fa7db 100644 --- a/drivers/acpi/acpi_pnp.c +++ b/drivers/acpi/acpi_pnp.c @@ -320,6 +320,9 @@ static bool matching_id(const char *idstr, const char *list_id) { int i; + if (strlen(idstr) != strlen(list_id)) + return false; + if (memcmp(idstr, list_id, 3)) return false; |