linux-kernel - [PATCH] power: supply: core: Ignore -EIO for uevent

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Message-Id: <20220824165459.1.I059ae712dd6d324897162ee9f37c22849aa22745@changeid>
Date:   Wed, 24 Aug 2022 16:57:20 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Sebastian Reichel <sre@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Brian Norris <briannorris@...omium.org>
Subject: [PATCH] power: supply: core: Ignore -EIO for uevent

For uevents, we enumerate all properties. Some battery implementations
don't implement all standard properties, and may return -EIO for
properties that aren't recognized. This means we never report uevents
for such batteries.

It's better to ignore these errors and skip the property, as we do with
ENODATA and ENODEV.

Example battery implementation: Acer Chromebook Tab 10 (a.k.a. Google
Gru-Scarlet) has a virtual "SBS" battery implementation in its Embedded
Controller on top of an otherwise non-SBS battery.

Signed-off-by: Brian Norris <briannorris@...omium.org>
---

 drivers/power/supply/power_supply_sysfs.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index 4239591e1522..36fce572a213 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -439,10 +439,12 @@ static int add_prop_uevent(struct device *dev, struct kobj_uevent_env *env,
 	dev_attr = &pwr_attr->dev_attr;
 
 	ret = power_supply_show_property(dev, dev_attr, prop_buf);
-	if (ret == -ENODEV || ret == -ENODATA) {
+	if (ret == -ENODEV || ret == -ENODATA || ret == -EIO) {
 		/*
 		 * When a battery is absent, we expect -ENODEV. Don't abort;
-		 * send the uevent with at least the the PRESENT=0 property
+		 * send the uevent with at least the PRESENT=0 property. Some
+		 * batteries also report EIO, even for some standard
+		 * properties.
 		 */
 		return 0;
 	}
-- 
2.37.2.672.g94769d06f0-goog