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udev-util: ignore USB-C ports in power source mode when detecting system is running on AC power

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Fixes #21988.
This commit is contained in:
Yu Watanabe
2022-01-06 18:28:56 +09:00
parent 01d4ad3bde
commit 795e86b4f1
1 changed files with 72 additions and 0 deletions
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src/shared/udev-util.c
+72
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@@ -580,6 +580,66 @@ int udev_queue_init(void) {
return TAKE_FD(fd);
}
static int device_is_power_sink(sd_device *device) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
bool found_source = false, found_sink = false;
sd_device *parent, *d;
int r;
assert(device);
/* USB-C power supply device has two power roles: source or sink. See,
* https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-typec */
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
r = sd_device_enumerator_allow_uninitialized(e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_subsystem(e, "typec", true);
if (r < 0)
return r;
r = sd_device_get_parent(device, &parent);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_parent(e, parent);
if (r < 0)
return r;
FOREACH_DEVICE(e, d) {
const char *val;
r = sd_device_get_sysattr_value(d, "power_role", &val);
if (r < 0) {
if (r != -ENOENT)
log_device_debug_errno(d, r, "Failed to read 'power_role' sysfs attribute, ignoring: %m");
continue;
}
if (strstr(val, "[source]")) {
found_source = true;
log_device_debug(d, "The USB type-C port is in power source mode.");
} else if (strstr(val, "[sink]")) {
found_sink = true;
log_device_debug(d, "The USB type-C port is in power sink mode.");
}
}
if (found_sink)
log_device_debug(device, "The USB type-C device has at least one port in power sink mode.");
else if (!found_source)
log_device_debug(device, "The USB type-C device has no port in power source mode, assuming the device is in power sink mode.");
else
log_device_debug(device, "All USB type-C ports are in power source mode.");
return found_sink || !found_source;
}
int on_ac_power(void) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
bool found_offline = false, found_online = false;
@@ -617,6 +677,18 @@ int on_ac_power(void) {
continue;
}
/* Ignore USB-C power supply in source mode. See issue #21988. */
if (streq(val, "USB")) {
r = device_is_power_sink(d);
if (r <= 0) {
if (r < 0)
log_device_debug_errno(d, r, "Failed to determine the current power role, ignoring: %m");
else
log_device_debug(d, "USB power supply is in source mode, ignoring.");
continue;
}
}
r = sd_device_get_sysattr_value(d, "online", &val);
if (r < 0) {
log_device_debug_errno(d, r, "Failed to read 'online' sysfs attribute, ignoring: %m");