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platform/chrome: cros_ec_proto: ignore unnecessary wakeups on old ECs

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ECs that don't implement EC_CMD_HOST_EVENT_GET_WAKE_MASK should still
have some reasonable default mask -- otherwise, they'll treat a variety
of EC signals as spurious wakeups. Battery and AC events can be
especially common, for devices that have been sitting at full charge
plugged into AC for a long time, as they may cycle their charging off
and on, or their battery may start reporting failures as it ages.

Treating these as wakeups does not serve a useful purpose, and is
instead often counterproductive. And indeed, later ECs (that implement
the mask) don't include these events in their wake-mask.

Note that this patch doesn't do anything without the subsequent patch
("platform/chrome: cros_ec_proto: check for missing
EC_CMD_HOST_EVENT_GET_WAKE_MASK"), because
cros_ec_get_host_event_wake_mask() currently does not return an error if
EC_CMD_HOST_EVENT_GET_WAKE_MASK is not implemented.

Some additional notes:
While the EC typically knows not to wake the CPU for these unimportant
events once the CPU reaches a sleep state, it doesn't really have a way
to know that the CPU is "almost" asleep, unless it has support for
EC_CMD_HOST_SLEEP_EVENT. Alas, these older ECs do not support that
command either, so this solution is not 100% complete.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
This commit is contained in:
Brian Norris 2020-07-24 12:08:40 -07:00 committed by Enric Balletbo i Serra
parent 7f4784f188
commit c214e564ac
1 changed files with 18 additions and 6 deletions
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24
drivers/platform/chrome/cros_ec_proto.c
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@ -469,14 +469,26 @@ int cros_ec_query_all(struct cros_ec_device *ec_dev)
&ver_mask);
ec_dev->host_sleep_v1 = (ret >= 0 && (ver_mask & EC_VER_MASK(1)));
/*
* Get host event wake mask, assume all events are wake events
* if unavailable.
*/
/* Get host event wake mask. */
ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg,
&ec_dev->host_event_wake_mask);
if (ret < 0)
ec_dev->host_event_wake_mask = U32_MAX;
if (ret < 0) {
/*
* If the EC doesn't support EC_CMD_HOST_EVENT_GET_WAKE_MASK,
* use a reasonable default. Note that we ignore various
* battery, AC status, and power-state events, because (a)
* those can be quite common (e.g., when sitting at full
* charge, on AC) and (b) these are not actionable wake events;
* if anything, we'd like to continue suspending (to save
* power), not wake up.
*/
ec_dev->host_event_wake_mask = U32_MAX &
~(BIT(EC_HOST_EVENT_AC_DISCONNECTED) |
BIT(EC_HOST_EVENT_BATTERY_LOW) |
BIT(EC_HOST_EVENT_BATTERY_CRITICAL) |
BIT(EC_HOST_EVENT_PD_MCU) |
BIT(EC_HOST_EVENT_BATTERY_STATUS));
}
ret = 0;