Hi Brian,
On 24/7/20 21:08, Brian Norris wrote:
> 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 <briannor...@chromium.org>
Sorry for late notice. The patch has been applied for 5.9.
> ---
> v2:
> * more notes in commit message
> ---
> drivers/platform/chrome/cros_ec_proto.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_proto.c
> b/drivers/platform/chrome/cros_ec_proto.c
> index 3e745e0fe092..e93024b55ce8 100644
> --- a/drivers/platform/chrome/cros_ec_proto.c
> +++ b/drivers/platform/chrome/cros_ec_proto.c
> @@ -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;
>
>
