From c851bc054e0d53a27516b09b071900a03a3cf67a Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Wed, 9 May 2018 12:12:15 -0700 Subject: [PATCH] HID: i2c-hid: check if device is there before really probing [ Upstream commit b3a81b6c4fc6730ac49e20d789a93c0faabafc98 ] On many Chromebooks touch devices are multi-sourced; the components are electrically compatible and one can be freely swapped for another without changing the OS image or firmware. To avoid bunch of scary messages when device is not actually present in the system let's try testing basic communication with it and if there is no response terminate probe early with -ENXIO. Signed-off-by: Dmitry Torokhov Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/hid/i2c-hid/i2c-hid.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index 00bce002b357..ce2b80009c19 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -1101,6 +1101,14 @@ static int i2c_hid_probe(struct i2c_client *client, pm_runtime_enable(&client->dev); device_enable_async_suspend(&client->dev); + /* Make sure there is something at this address */ + ret = i2c_smbus_read_byte(client); + if (ret < 0) { + dev_dbg(&client->dev, "nothing at this address: %d\n", ret); + ret = -ENXIO; + goto err_pm; + } + ret = i2c_hid_fetch_hid_descriptor(ihid); if (ret < 0) goto err_pm;