From: Zbigniew Jędrzejewski-Szmek Date: Tue, 23 Aug 2022 14:30:05 +0000 (+0200) Subject: on-ac-power: rework logic X-Git-Tag: v252-rc1~356^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a52514b371bf8013e89c421dfc2405a443feef8;p=thirdparty%2Fsystemd.git on-ac-power: rework logic History of the function: 96788d2aa4f4b0b49874b4a240ce47d9e8485d1b assume system is running on AC power when no battery found 795e86b4f1e8a1fd440f8c817621779c6aedbdb5 ignore USB-C ports in power source mode when detecting system is running on AC power c19a51bec40ae5e5073464e72411e7920d05d683 invert ac_power() source type check 6d89003462484c8656b698e07b9cf0a337e3818e assume ac when /sys/class/power_supply is missing 240dbaa44f8e5ad51775c776fc3ce9cd2f19f037 add ConditionACPower= Interestingly, the return condition 'on_ac_power == found_online || !found_offline' was there from the very beginning, and even Yu's latest change doesn't change this, but only extends it to 'on_ac_power == found_online || !found_offline || !found_battery'. This means that any system with no AC power supply will be unconditionally classified as on_ac_power. Let's change the logic: if we have an online AC supply, answer is "yes". If no supplies, but we have a battery, answer is "no". Otherwise, assume "yes", based on the assumption that presense of a battery would at least be always reported, even if an AC power supply might not be. Fixes #24407. It also shouldn't impact previous fixes: assume ac when /sys/class/power_supply is missing, ignore USB-C ports in power source mode, assume system is running on AC power when no battery found. --- diff --git a/src/shared/udev-util.c b/src/shared/udev-util.c index db968a17c47..8892d2bc9a9 100644 --- a/src/shared/udev-util.c +++ b/src/shared/udev-util.c @@ -661,7 +661,7 @@ static int device_is_power_sink(sd_device *device) { int on_ac_power(void) { _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL; - bool found_offline = false, found_online = false, found_battery = false; + bool found_ac_online = false, found_battery = false; sd_device *d; int r; @@ -678,25 +678,18 @@ int on_ac_power(void) { return r; FOREACH_DEVICE(e, d) { - const char *val; - unsigned v; + /* See + * https://github.com/torvalds/linux/blob/4eef766b7d4d88f0b984781bc1bcb574a6eafdc7/include/linux/power_supply.h#L176 + * for defined power source types. Also see: + * https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-power */ + const char *val; r = sd_device_get_sysattr_value(d, "type", &val); if (r < 0) { log_device_debug_errno(d, r, "Failed to read 'type' sysfs attribute, ignoring device: %m"); continue; } - /* We assume every power source is AC, except for batteries. See - * https://github.com/torvalds/linux/blob/4eef766b7d4d88f0b984781bc1bcb574a6eafdc7/include/linux/power_supply.h#L176 - * for defined power source types. Also see: - * https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-power */ - if (streq(val, "Battery")) { - found_battery = true; - log_device_debug(d, "The power supply is battery, ignoring device."); - continue; - } - /* Ignore USB-C power supply in source mode. See issue #21988. */ if (streq(val, "USB")) { r = device_is_power_sink(d); @@ -709,36 +702,33 @@ int on_ac_power(void) { } } - 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 device: %m"); + bool is_battery = streq(val, "Battery"); + if (is_battery) { + found_battery = true; + log_device_debug(d, "The power supply is battery."); continue; } - r = safe_atou(val, &v); + r = device_get_sysattr_unsigned(d, "online", NULL); if (r < 0) { - log_device_debug_errno(d, r, "Failed to parse 'online' attribute, ignoring device: %m"); + log_device_debug_errno(d, r, "Failed to query 'online' sysfs attribute: %m"); continue; - } - - if (v > 0) /* At least 1 and 2 are defined as different types of 'online' */ - found_online = true; - else - found_offline = true; + } else if (r > 0) /* At least 1 and 2 are defined as different types of 'online' */ + found_ac_online = true; - log_device_debug(d, "The power supply is currently %s.", v > 0 ? "online" : "offline"); + log_device_debug(d, "The power supply is currently %s.", r > 0 ? "online" : "offline"); } - if (found_online) - log_debug("Found at least one online non-battery power supply, system is running on AC power."); - else if (!found_offline) - log_debug("Found no offline non-battery power supply, assuming system is running on AC power."); - else if (!found_battery) - log_debug("Found no battery, assuming system is running on AC power."); - else - log_debug("All non-battery power supplies are offline, assuming system is running with battery."); - - return found_online || !found_offline || !found_battery; + if (found_ac_online) { + log_debug("Found at least one online non-battery power supply, system is running on AC."); + return true; + } else if (found_battery) { + log_debug("Found battery and no online power sources, assuming system is running from battery."); + return false; + } else { + log_debug("No power supply reported online and no battery, assuming system is running on AC."); + return true; + } } bool udev_available(void) {