Re: A different PD controller firmware problem?

["Theodore Y. Ts'o" <tytso@mit.edu>]

On Thu, Nov 08, 2018 at 04:15:40PM -0500, Theodore Y. Ts'o wrote:
> On Thu, Nov 08, 2018 at 06:00:59PM +0000, Mario.Limonciello@dell.com wrote:
> > > Sortly after 12:30am US/Eastern, I got a low power warning on my
> > > system, and the battery power had dropped below 10%.  Apparently the
> > > laptop was not accepting any charge any more.  I tried doing a suspend
> > > to ram, and then unsuspended it, and it still wasn't accepting any
> > > charge, even though the adapter indicated it was plugged in and
> > > supplying power.  I then did a power cycle, and still the laptop
> > > didn't indicate it was charging with a USB C 45W power supply plugged
> > > in.
> > 
> > Just to be clear was this a Dell adapter or another manufacturer?
> > 
> > If it's non-Dell, there could easily be an untested combination of controllers
> > and one getting into a bad state.

It happened again, just now.  Unfortunately I didn't have a Dell
charger handy when it did, but it was the same symptoms.  One
interesting thing that I did discover is that by observing the voltage
being negotiated via USB-C PD, using a Satechi USB-C power monitor, I
discovered that when the laptop gets into this state, while the laptop
is suspended or powered off, it will negotiate to 5 volts at 3 amps
(assuming the power supply supports it).  So apparently the problem is
that the PD controller on the XPS 13 was refusing to negotiate any
other voltage *besides* 5 volts.  The fact that it could negotiate 3
amps means that it was doing USB-C PD negotiation; it was just doing
so... badly.

As before, the problem persisted across multiple USB-C power sources,
and I could switch between them so long as the laptop was booted into
Linux, suspended, or powered off but with a power supply attached.
The way the problem got fixed is by unplugging the power supply with
the laptop in a powered of state.  Apparently that (and only that)
will reset the problem in the EC or USB-C PD controller.

If there is something that I should try next time (other than trying
to use a Dell USB-C power supply; I'll start carrying it around in the
future), please let me know.  I couldn't find any obvious EC Logs that
I could download, unfortunately.

Firmware versions:

<tytso.root@cwcc> {/usr/projects/linux/ext4-fsverity}, level 2   (master)
1008# fwupdmgr get-devices
XPS 13 9370 System Firmware
  DeviceId:             8a21cacfb0a8d2b30c5ee9290eb71db021619f8b
  Guid:                 7ceaf7a8-0611-4480-9e30-64d8de420c7c
  Guid:                 43ea5588-d9a4-5031-8ad3-308045302d6b
  Guid:                 230c8b18-8d9b-53ec-838b-6cfc0383493a
  Plugin:               uefi
  Flags:                internal|updatable|require-ac|supported|registered|needs-reboot
  Version:              0.1.5.1
  VersionLowest:        0.1.5.1
  Icon:                 computer
  Created:              2018-11-10

KXG50ZNV1T02 NVMe TOSHIBA 1024GB
  DeviceId:             f954c7acdf5fab61aeaca1cd71d29ea5ade6992f
  Guid:                 4d0aed03-a30c-52c6-99e7-a8977797c3d9
  Guid:                 ad9fe8f7-cdc4-52c9-9fea-31b6f4988ffa
  Serial:               Y77S10C8TYAT
  Summary:              NVM Express Solid State Drive
  Plugin:               nvme
  Flags:                internal|updatable|require-ac|registered|needs-reboot
  Vendor:               Toshiba America Info Systems
  VendorId:             NVME:0x1179
  Version:              AADA4102
  Icon:                 drive-harddisk
  Created:              2018-11-10

XPS 13 9370 Thunderbolt Controller
  DeviceId:             8885ea984074c84d636e5458d6b6d12649df2e5d
  Guid:                 4eeb9d07-a96c-56d6-92d3-4a23ee7a6e4a
  Summary:              Unmatched performance for high-speed I/O
  Plugin:               thunderbolt
  Flags:                internal|updatable|supported|registered
  Vendor:               Dell
  VendorId:             TBT:0x00D4
  Version:              33.00
  Icon:                 computer
  Created:              2018-11-10