serdev: Don't claim unsupported ACPI serial devices
authorPunit Agrawal <punit1.agrawal@toshiba.co.jp>
Thu, 19 Dec 2019 10:03:45 +0000 (19:03 +0900)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 14 Jan 2020 19:07:05 +0000 (20:07 +0100)
commit8b16b0cb36a1f8ed8f04f3602c9f501feeda336e
treed86b9a1ced206be9f89ec83c136dc8a177cbaab0
parent200d4eb8fdc0a0573454b0c3281e0ca9f317aa65
serdev: Don't claim unsupported ACPI serial devices

commit c5ee0b3104e0b292d353e63fd31cb8c692645d8c upstream.

Serdev sub-system claims all ACPI serial devices that are not already
initialised. As a result, no device node is created for serial ports
on certain boards such as the Apollo Lake based UP2. This has the
unintended consequence of not being able to raise the login prompt via
serial connection.

Introduce a blacklist to reject ACPI serial devices that should not be
claimed by serdev sub-system. Add the peripheral ids for Intel HS UART
to the blacklist to bring back serial port on SoCs carrying them.

Cc: stable@vger.kernel.org
Signed-off-by: Punit Agrawal <punit1.agrawal@toshiba.co.jp>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Johan Hovold <johan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20191219100345.911093-1-punit1.agrawal@toshiba.co.jp
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serdev/core.c