diff options
| author | Hui Wang <hui.wang@canonical.com> | 2020-12-11 05:18:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-12-30 13:51:32 +0300 |
| commit | 2c6c6001d07758cf79fc57c705b763d955e1922c (patch) | |
| tree | d572d72fce01bccb8ed939ce8a100fa597590482 /drivers/acpi | |
| parent | 772dd826a44bd6f44b2c517a6b0c690f7ae9e4cd (diff) | |
| download | linux-2c6c6001d07758cf79fc57c705b763d955e1922c.tar.xz | |
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 f3039b93ff61..101887528848 100644 --- a/drivers/acpi/acpi_pnp.c +++ b/drivers/acpi/acpi_pnp.c @@ -317,6 +317,9 @@ 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; |