Hi, On Tue, Jun 02, 2020 at 09:17:09AM +0200, Marek Szyprowski wrote: > 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. Ok, I pushed out a revert of those two patches. They should land in tomorrows linux-next release. Please test it. > > 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. So basically userspace slows down itself massively by trying to re-read uevent over and over when an error occurs. Does not seem like a sensible thing to do. I will have a look at this when I find some time. -- Sebastian
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