Hi Sebastian, On 01.06.2020 19:05, Sebastian Reichel wrote: > On Mon, Jun 01, 2020 at 12:40:27PM +0200, Marek Szyprowski wrote: >> On 13.05.2020 20:55, Sebastian Reichel wrote: >>> This patchset improves support for SBS compliant batteries. Due to >>> the changes, the battery now exposes 32 power supply properties and >>> (un)plugging it generates a backtrace containing the following message >>> without the first patch in this series: >>> >>> --------------------------- >>> WARNING: CPU: 0 PID: 20 at lib/kobject_uevent.c:659 add_uevent_var+0xd4/0x104 >>> add_uevent_var: too many keys >>> --------------------------- >>> >>> For references this is what an SBS battery status looks like after >>> the patch series has been applied: >>> >>> cat /sys/class/power_supply/sbs-0-000b/uevent >>> POWER_SUPPLY_NAME=sbs-0-000b >>> POWER_SUPPLY_TYPE=Battery >>> POWER_SUPPLY_STATUS=Discharging >>> POWER_SUPPLY_CAPACITY_LEVEL=Normal >>> POWER_SUPPLY_HEALTH=Good >>> POWER_SUPPLY_PRESENT=1 >>> POWER_SUPPLY_TECHNOLOGY=Li-ion >>> POWER_SUPPLY_CYCLE_COUNT=12 >>> POWER_SUPPLY_VOLTAGE_NOW=11441000 >>> POWER_SUPPLY_CURRENT_NOW=-26000 >>> POWER_SUPPLY_CURRENT_AVG=-24000 >>> POWER_SUPPLY_CAPACITY=76 >>> POWER_SUPPLY_CAPACITY_ERROR_MARGIN=1 >>> POWER_SUPPLY_TEMP=198 >>> POWER_SUPPLY_TIME_TO_EMPTY_AVG=438600 >>> POWER_SUPPLY_TIME_TO_FULL_AVG=3932100 >>> POWER_SUPPLY_SERIAL_NUMBER=0000 >>> POWER_SUPPLY_VOLTAGE_MIN_DESIGN=10800000 >>> POWER_SUPPLY_VOLTAGE_MAX_DESIGN=10800000 >>> POWER_SUPPLY_ENERGY_NOW=31090000 >>> POWER_SUPPLY_ENERGY_FULL=42450000 >>> POWER_SUPPLY_ENERGY_FULL_DESIGN=41040000 >>> POWER_SUPPLY_CHARGE_NOW=2924000 >>> POWER_SUPPLY_CHARGE_FULL=3898000 >>> POWER_SUPPLY_CHARGE_FULL_DESIGN=3800000 >>> POWER_SUPPLY_CONSTANT_CHARGE_CURRENT_MAX=3000000 >>> POWER_SUPPLY_CONSTANT_CHARGE_VOLTAGE_MAX=12300000 >>> POWER_SUPPLY_MANUFACTURE_YEAR=2017 >>> POWER_SUPPLY_MANUFACTURE_MONTH=7 >>> POWER_SUPPLY_MANUFACTURE_DAY=3 >>> POWER_SUPPLY_MANUFACTURER=UR18650A >>> POWER_SUPPLY_MODEL_NAME=GEHC >> This patch landed in linux-next dated 20200529. Sadly it causes a >> regression on Samsung Exynos-based Chromebooks (Exynos5250 Snow, >> Exynos5420 Peach-Pi and Exynos5800 Peach-Pit). System boots to >> userspace, but then, when udev populates /dev, booting hangs: >> >> [ 4.435167] VFS: Mounted root (ext4 filesystem) readonly on device >> 179:51. >> [ 4.457477] devtmpfs: mounted >> [ 4.460235] Freeing unused kernel memory: 1024K >> [ 4.464022] Run /sbin/init as init process >> INIT: version 2.88 booting >> [info] Using makefile-style concurrent boot in runlevel S. >> [ 5.102096] random: crng init done >> [....] Starting the hotplug events dispatcher: systemd-udevdstarting >> version 236 >> [ ok . >> [....] Synthesizing the initial hotplug events...[ ok done. >> [....] Waiting for /dev to be fully populated...[ 34.409914] >> TPS65090_RAILSDCDC1: disabling >> [ 34.412977] TPS65090_RAILSDCDC2: disabling >> [ 34.417021] TPS65090_RAILSDCDC3: disabling >> [ 34.423848] TPS65090_RAILSLDO1: disabling >> [ 34.429068] TPS65090_RAILSLDO2: disabling > :( > > log does not look useful either. > >> Bisect between v5.7-rc1 and next-20200529 pointed me to the first bad >> commit: [c4b12a2f3f3de670f6be5e96092a2cab0b877f1a] power: supply: >> sbs-battery: simplify read_read_string_data. > ok. I tested this on an to-be-upstreamed i.MX6 based system > and arch/arm/boot/dts/imx53-ppd.dts. I think the difference > is, that i2c-exynos5 does not expose I2C_FUNC_SMBUS_READ_BLOCK_DATA. > I hoped all systems using SBS battery support this, but now > I see I2C_FUNC_SMBUS_EMUL only supports writing block data. > Looks like I need to add another patch implementing that > using the old code with added PEC support. > > In any case that should only return -ENODEV for the property > (and uevent), but not break boot. So something fishy is going > on. > >> However reverting it in linux-next doesn't fix the issue, so the >> next commits are also relevant to this issue. > The next patch, which adds PEC support depends on the simplification > of sbs_read_string_data. The old, open coded variant will result in > PEC failure for string properties (which should not stop boot either > of course). Can you try reverting both? Indeed, reverting both (and fixing the conflict) restores proper boot. > If that helps I will revert those two instead of dropping the whole > series for this merge window. > >> Let me know how can I help debugging it. > I suspect, that this is userspace endlessly retrying reading the > battery uevent when an error is returned. Could you check this? > Should be easy to see by adding some printfs. I've added some debug messages in sbs_get_property() and it read the same properties many times. However I've noticed that if I wait long enough booting finally continues. > That would mean a faulty battery could stall complete boot without > a useful error message, which is bad and needs to be fixed. > > Sorry for the inconvience and thanks for your report, No problem, finding regressions is one of the linux-next goal. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
