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From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel@collabora.com,
	'Linux Samsung SOC' <linux-samsung-soc@vger.kernel.org>
Subject: Re: [PATCHv1 00/19] Improve SBS battery support
Date: Tue, 2 Jun 2020 09:17:09 +0200	[thread overview]
Message-ID: <b3fd35de-1dd6-1ddc-7e57-2d9ab2860e81@samsung.com> (raw)
In-Reply-To: <20200601170528.r5w3aeijny3v5yx3@earth.universe>

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


  reply	other threads:[~2020-06-02  7:17 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-13 18:55 Sebastian Reichel
2020-05-13 18:55 ` [PATCHv1 01/19] kobject: increase allowed number of uevent variables Sebastian Reichel
2020-05-14  6:11   ` Greg Kroah-Hartman
2020-05-15 14:45   ` Emil Velikov
2020-05-13 18:55 ` [PATCHv1 02/19] power: supply: core: add capacity error margin property Sebastian Reichel
2020-05-13 18:55 ` [PATCHv1 03/19] power: supply: core: add manufacture date properties Sebastian Reichel
2020-05-15 14:47   ` Emil Velikov
2020-05-15 15:14     ` Sebastian Reichel
2020-05-15 16:01       ` Emil Velikov
2020-05-13 18:56 ` [PATCHv1 04/19] power: supply: core: add POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 05/19] power: supply: sbs-battery: Add TI BQ20Z65 support Sebastian Reichel
2020-05-28  2:37   ` Rob Herring
2020-05-13 18:56 ` [PATCHv1 06/19] power: supply: sbs-battery: add POWER_SUPPLY_PROP_CAPACITY_ERROR_MARGIN support Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 07/19] power: supply: sbs-battery: simplify read_read_string_data Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 08/19] power: supply: sbs-battery: add PEC support Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 09/19] power: supply: sbs-battery: add POWER_SUPPLY_PROP_CURRENT_AVG support Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 10/19] power: supply: sbs-battery: Improve POWER_SUPPLY_PROP_TECHNOLOGY support Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 11/19] power: supply: sbs-battery: add POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT/VOLTAGE_MAX support Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 12/19] power: supply: sbs-battery: add MANUFACTURE_DATE support Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 13/19] power: supply: sbs-battery: add POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED support Sebastian Reichel
2020-05-15 15:35   ` Emil Velikov
2020-05-13 18:56 ` [PATCHv1 14/19] power: supply: sbs-battery: fix idle battery status Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 15/19] power: supply: sbs-battery: add ability to disable charger broadcasts Sebastian Reichel
2020-05-15 14:57   ` Emil Velikov
2020-05-13 18:56 ` [PATCHv1 16/19] power: supply: sbs-battery: switch from of_property_* to device_property_* Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 17/19] power: supply: sbs-battery: switch to i2c's probe_new Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 18/19] power: supply: sbs-battery: constify power-supply property array Sebastian Reichel
2020-05-13 18:56 ` [PATCHv1 19/19] dt-bindings: power: sbs-battery: Convert to yaml Sebastian Reichel
2020-05-28  2:40   ` Rob Herring
2020-05-28 22:44 ` [PATCHv1 00/19] Improve SBS battery support Sebastian Reichel
2020-05-29 16:27 ` Pavel Machek
2020-06-01 21:57   ` Sebastian Reichel
     [not found] ` <CGME20200601104027eucas1p2b076ee860520d709e8178c41550653f7@eucas1p2.samsung.com>
2020-06-01 10:40   ` Marek Szyprowski
2020-06-01 17:05     ` Sebastian Reichel
2020-06-02  7:17       ` Marek Szyprowski [this message]
2020-06-02 18:01         ` Sebastian Reichel
2020-06-03 18:49           ` Marek Szyprowski

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