From: Patryk Duda pdk@semihalf.com
commit 3abc16af57c9939724df92fcbda296b25cc95168 upstream.
Sometimes kernel is trying to probe Fingerprint MCU (FPMCU) when it hasn't initialized SPI yet. This can happen because FPMCU is restarted during system boot and kernel can send message in short window eg. between sysjump to RW and SPI initialization.
Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Patryk Duda pdk@semihalf.com Link: https://lore.kernel.org/r/20210518140758.29318-1-pdk@semihalf.com Signed-off-by: Benson Leung bleung@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/platform/chrome/cros_ec_proto.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/drivers/platform/chrome/cros_ec_proto.c +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -219,6 +219,15 @@ static int cros_ec_host_command_proto_qu msg->insize = sizeof(struct ec_response_get_protocol_info);
ret = send_command(ec_dev, msg); + /* + * Send command once again when timeout occurred. + * Fingerprint MCU (FPMCU) is restarted during system boot which + * introduces small window in which FPMCU won't respond for any + * messages sent by kernel. There is no need to wait before next + * attempt because we waited at least EC_MSG_DEADLINE_MS. + */ + if (ret == -ETIMEDOUT) + ret = send_command(ec_dev, msg);
if (ret < 0) { dev_dbg(ec_dev->dev,