4.4-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Torokhov dtor@chromium.org
[ 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 dtor@chromium.org Reviewed-by: Benjamin Tissoires benjamin.tissoires@redhat.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hid/i2c-hid/i2c-hid.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -1017,6 +1017,14 @@ static int i2c_hid_probe(struct i2c_clie pm_runtime_set_active(&client->dev); pm_runtime_enable(&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;