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authorEvan Green <evgreen@chromium.org>2019-06-27 13:44:45 -0700
committerEnric Balletbo i Serra <enric.balletbo@collabora.com>2019-07-01 15:39:11 +0200
commit8c3166e17cf10161d2871dfb1d017287c7b79ff1 (patch)
treed5a236fb41c68187aac195ba0c4033bd8a428713 /Documentation/ABI
parentc18e6ea1014ca1ade0030aca5e80af33c8873e1e (diff)
mfd / platform: cros_ec_debugfs: Expose resume result via debugfs
For ECs that support it, the EC returns the number of slp_s0 transitions and whether or not there was a timeout in the resume response. Expose the last resume result to usermode via debugfs so that usermode can detect and report S0ix timeouts. Signed-off-by: Evan Green <evgreen@chromium.org> Acked-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/debugfs-cros-ec22
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/debugfs-cros-ec b/Documentation/ABI/testing/debugfs-cros-ec
index 573a82d23c89..1fe0add99a2a 100644
--- a/Documentation/ABI/testing/debugfs-cros-ec
+++ b/Documentation/ABI/testing/debugfs-cros-ec
@@ -32,3 +32,25 @@ Description:
is used for synchronizing the AP host time with the EC
log. An error is returned if the command is not supported
by the EC or there is a communication problem.
+
+What: /sys/kernel/debug/<cros-ec-device>/last_resume_result
+Date: June 2019
+KernelVersion: 5.3
+Description:
+ Some ECs have a feature where they will track transitions to
+ the (Intel) processor's SLP_S0 line, in order to detect cases
+ where a system failed to go into S0ix. When the system resumes,
+ an EC with this feature will return a summary of SLP_S0
+ transitions that occurred. The last_resume_result file returns
+ the most recent response from the AP's resume message to the EC.
+
+ The bottom 31 bits contain a count of the number of SLP_S0
+ transitions that occurred since the suspend message was
+ received. Bit 31 is set if the EC attempted to wake the
+ system due to a timeout when watching for SLP_S0 transitions.
+ Callers can use this to detect a wake from the EC due to
+ S0ix timeouts. The result will be zero if no suspend
+ transitions have been attempted, or the EC does not support
+ this feature.
+
+ Output will be in the format: "0x%08x\n".