commit eef4016243 upstream.
Before this commit i2c_hid_parse() consists of the following steps:
1. Send power on cmd
2. usleep_range(1000, 5000)
3. Send reset cmd
4. Wait for reset to complete (device interrupt, or msleep(100))
5. Send power on cmd
6. Try to read HID descriptor
Notice how there is an usleep_range(1000, 5000) after the first power-on
command, but not after the second power-on command.
Testing has shown that at least on the BMAX Y13 laptop's i2c-hid touchpad,
not having a delay after the second power-on command causes the HID
descriptor to read as all zeros.
In case we hit this on other devices too, the descriptor being all zeros
can be recognized by the following message being logged many, many times:
hid-generic 0018:0911:5288.0002: unknown main item tag 0x0
At the same time as the BMAX Y13's touchpad issue was debugged,
Kai-Heng was working on debugging some issues with Goodix i2c-hid
touchpads. It turns out that these need a delay after a PWR_ON command
too, otherwise they stop working after a suspend/resume cycle.
According to Goodix a delay of minimal 60ms is needed.
Having multiple cases where we need a delay after sending the power-on
command, seems to indicate that we should always sleep after the power-on
command.
This commit fixes the mentioned issues by moving the existing 1ms sleep to
the i2c_hid_set_power() function and changing it to a 60ms sleep.
Cc: stable@vger.kernel.org
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208247
Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reported-and-tested-by: Andrea Borgia <andrea@borgia.bo.it>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
c2035d1e55