tree a15e9a521e9543d9d55575652a3700a048504c70
parent 07aabdfb70e88891f587599a13c2303f7decbacc
author Richard Yeh <rcy@google.com> 1721877121 +0000
committer Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> 1722463808 +0000

mimo-monitor: Adjust reset approach.

With M120, there was an increased number of MIMO devices where the touch
panel would spontaneously disconnect from the system.  The mimo-monitor
is a watchdog process that verifies the MIMO components each minute and
attempts to reset any components that have disappeared.

Reading the code, there are assumptions that the device pointer is valid
at several places.  Instead, the device may have disappeared, so we
check function return values (particularly ReadID) more carefully.  If
the touch panel is unavailable, attempt to reset the parent device:
there is no way to send a reset command to an unresponsive device.

Add a throttle so that we do not reset the parent device more than three
times in every ten minutes.

I `cros deploy` this to an ambassador device, and then `lsusb; lsusb -t`
to discover the bus and port numbers for the SiS touch controller.  Then
`echo '1-2.1' > /sys/bus/usb/drivers/usb/unbind` to disable the touch
controller.  Nothing happened.  The device still appears in `lsusb` but
not `lsusb -t`. `mimo-monitor` does not seem to notice.

BUG=b:340905255
TEST=cros deploy mimo-monitor

Change-Id: I727a5c6874ae51c0f82042dd51903e3f3e3e5eaa
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/cfm-device-monitor/+/5738592
Tested-by: Richard Yeh <rcy@google.com>
Commit-Queue: Richard Yeh <rcy@google.com>
Reviewed-by: Pablo Ceballos <pceballos@chromium.org>
(cherry picked from commit 6850e1dd1d63908d15126c431e95fbaa4a9a3289)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/cfm-device-monitor/+/5754104
Auto-Submit: Richard Yeh <rcy@google.com>