From d0a934b764c67b4bf626f5b7cf725a6e3066afd2 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Mon, 13 May 2013 15:01:30 +0000 Subject: HID: input: return ENODATA if reading battery attrs fails power_supply core has the bad habit of calling our battery callbacks from within power_supply_register(). Furthermore, if the callbacks fail with an unhandled error code, it will skip any uevent that it might currently process. So if HID-core registers battery devices, an "add" uevent is generated and the battery callbacks are called. These will gracefully fail due to timeouts as they might still hold locks on event processing. One could argue that this should be fixed in power_supply core, but the least we can do is to signal ENODATA so power_supply core will just skip the property and continue with the uevent. This fixes a bug where "add" and "remove" uevents are skipped for battery devices. upower is unable to track these devices and currently needs to ignore them. This patch also overwrites any other error code. I cannot see any reason why we should forward protocol- or I/O-errors to the power_supply core. We handle these errors in hid_ll_driver later, anyway, so just skip them. power_supply core cannot do anything useful with them, anyway, and we avoid skipping important uevents and confusing user-space. Thanks a lot to Daniel Nicoletti for pushing and investigating on this. Cc: Jiri Kosina Cc: Anton Vorontsov Cc: David Woodhouse Reported-by: Daniel Nicoletti Signed-off-by: David Herrmann Signed-off-by: Jiri Kosina --- diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 945b815..c526a3c 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -354,10 +354,10 @@ static int hidinput_get_battery_property(struct power_supply *psy, dev->battery_report_type); if (ret != 2) { - if (ret >= 0) - ret = -EINVAL; + ret = -ENODATA; break; } + ret = 0; if (dev->battery_min < dev->battery_max && buf[1] >= dev->battery_min && -- cgit v0.9.2