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Issue 889959 link

Starred by 2 users
Status: Started
Owner:
adlr@chromium.org
Cc:
bleung@chromium.org
█ dtor@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 1
Type: Feature



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touch_updater: Allow vendors to opt out of restoring power state after rebind

Project Member Reported by adlr@chromium.org, Sep 27 
Currently the touch updater behavior is:

- store all touch device paths
- set all touch device paths to full power (from 'auto')
- for each device:
- if (needs update)
--  do update
--  rebind (may move device to new path)
- for each stored path from the beginning,
--  set power state back to auto

The last step will fail if a rebind of a device caused it to move to a new path. However, in this case, we can skip restoring the path b/c the new device will come up in 'auto'. Benson may elaborate below on why this is okay.

We will add a facility to allow restoring power state to be skipped

Comment 1 by bleung@chromium.org, Sep 27

Cc: dtor@chromium.org
Components: Internals>Input>Touch>Pad Internals>Input>Touch>Screen
Thanks adlr.

Here's why I think this is the right approach:

When an update occurs and the driver is rebound, the new instance of the device will come up with default settings for power/control anyway (just like start of day for the device and driver).

Furthermore, since it's a new device that's just appeared, on a real system, the power manager should detect it and take control of power/control and write it the correct value (auto most likely).

So looking for the device and restoring its power state in the update script after an update is unnecessary.
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