On Sat, 2022-10-29 at 16:55 +0200, José Expósito wrote: > Hi! > > On Sat, Oct 29, 2022 at 04:55:21PM +0300, Mia Kanashi wrote: > > > > [1] Actually it should be set to discharging until this gets > > > > merged: > > > > > > > > https://lore.kernel.org/linux-input/20221028181849.23157-1-jose.exposito89@xxxxxxxxx/T/ > > > > > > But i also currently applied this ^ patch, i will try testing > > > without it and then report. > > > > Tested without it, same issue. > > So yeah it seems that hid-input driver can set supply status to > > discharging before setting a battery capacity? > > Very good catch. I managed to reproduce it using the USB dongle. I > didn't notice it before because I was running upower after connecting > the device, which isn't fast enough. However, using watch as you > suggested makes the issue pretty noticeable. > > The problem is that the battery is fetched when the USB dongle is > connected. However, the tablet might not be paired at that point. > > To explain it with the actual code: > > > if (dev->battery_status != HID_BATTERY_REPORTED && > !dev->battery_avoid_query) { > value = hidinput_query_battery_capacity(dev); > ^ Here the battery is fetched, but because the tabled > is not paired and this function returns garbage > if (value < 0) > return value; > > dev->battery_capacity = value; > dev->battery_status = HID_BATTERY_QUERIED; > ^ Now the battery is set as queried > } > > if (dev->battery_status == HID_BATTERY_UNKNOWN) > val->intval = POWER_SUPPLY_STATUS_UNKNOWN; > else > val->intval = POWER_SUPPLY_STATUS_DISCHARGING; > ^ And therefore the battery is reported > > > Thankfully, there is already a flag (battery_avoid_query) used to > solve > the same issue on stylus. The battery percentage is unknown until the > stylus is in proximity. > > So I guess I could use the same flag to avoid this problem. > > I'll add a fix in a second revision of this patch. UPower will also respect the POWER_SUPPLY_PROP_PRESENT property, if that's useful.
