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x1e80100 USB PD Charging Fix for Linux

Fix for extremely slow USB-C Power Delivery charging on Qualcomm Snapdragon X Elite (X1E80100) laptops running Linux. Increases charging from ~12W to 60W+ (5x improvement).

Tested on ASUS Vivobook S 15 / Vivobook S Plus X Elite (S5507QA) — should work on any X1E80100 laptop including Dell Latitude 7455, Lenovo ThinkPad T14s Gen 6, HP EliteBook Ultra, Samsung Galaxy Book4 Edge, and other Snapdragon X Elite / X Plus devices.

Keywords: Snapdragon X Elite, X1E80100, USB-C slow charging, Linux, Ubuntu, qcom_battmgr, PMIC GLINK, power delivery, ASUS Vivobook, Dell Latitude, Lenovo ThinkPad, battery charging fix

The Problem

On Snapdragon X Elite / X Plus laptops (ASUS Vivobook S 15, Vivobook S Plus X Elite, Dell Latitude 7455, Lenovo ThinkPad T14s Gen 6, etc.), USB-C PD charging under Linux is often limited to ~12W regardless of charger wattage. Windows charges the same hardware at 60W+ with the same charger.

Symptoms:

  • power_now reports only 10-15W while charging
  • qcom-battmgr-ac shows ONLINE=0 (system doesn't recognize AC power)
  • qcom-battmgr-usb shows ONLINE=1 but with USB_TYPE=Unknown
  • UCSI layer sees PD (USB_TYPE=C [PD] PD_PPS) but battery manager doesn't
  • Charging takes 5+ hours on a laptop that should charge in ~1.5 hours

Root Cause

The upstream qcom_battmgr driver maps X1E80100 to the QCOM_BATTMGR_SC8280XP variant, which:

  1. Only exposes ONLINE for USB — no voltage, current, or type information
  2. Never queries USB properties from firmware individually (uses bulk battery status notifications only)
  3. Never sets USB adapter type — firmware defaults to basic USB classification instead of PD
  4. Never uses BATTMGR_USB_PROPERTY_SET — opcode 0x33 exists but is dead code

The PMIC firmware classifies the charger as basic USB and limits charging current accordingly.

The Fix

This patch creates a dedicated QCOM_BATTMGR_X1E80100 variant that:

  1. Separates X1E80100 from SC8280XP — allows X1E-specific behavior
  2. Hybrid callback routing — uses SC8280XP-style callbacks for battery status notifications, SM8350-style individual property queries for USB properties
  3. Auto-configures PD on charger detect — sends USB_ADAP_TYPE=PD, USB_TYPE=PD, USB_CURR_MAX, USB_INPUT_CURR_LIMIT, and USB_VOLT_MAX to firmware when USB charging is detected
  4. Exposes full USB properties — voltage, current, type, and writable input_current_limit via sysfs
  5. Module parameter — pd_current_limit_ua (default 5A) for tuning

Results

Before After
Battery charging power ~12W ~61W
UCSI current draw 2.5A 4.3A
USB type reported Unknown PD
Charger input power ~15W ~86W (20V × 4.3A)
Time to full (70Wh battery) ~6 hours ~1.2 hours

Tested with a 100W USB-C PD charger. The firmware properly renegotiates the PD contract to draw up to 4.3A at 20V after the patch configures adapter type and current limits.

Tested On

  • Laptop: ASUS Vivobook S 15 / Vivobook S Plus X Elite (S5507QA / S5507QAD)
  • SoC: Qualcomm Snapdragon X Elite (X1E80100)
  • OS: Ubuntu 25.10 (Questing Quokka)
  • Kernel: 6.17.0-12-generic (aarch64)
  • Charger: 100W USB-C PD (InMotion) — capped at 60W by laptop's PD sink capability

Expected Compatible Devices

Any laptop with qcom,x1e80100-pmic-glink in its device tree, including:

  • ASUS Vivobook S 15 / S Plus X Elite (S5507QA, S5507QAD)
  • Dell Latitude 7455
  • Dell Inspiron 14 Plus
  • Lenovo ThinkPad T14s Gen 6
  • HP EliteBook Ultra G1q
  • Samsung Galaxy Book4 Edge
  • Microsoft Surface Laptop 7
  • Acer Swift 14 AI
  • Other Snapdragon X Elite / X Plus laptops

Please report your results if you test on a different device!

Installation

Prerequisites

sudo apt install build-essential linux-headers-$(uname -r)

Build

git clone https://github.com/PenguinzTech/x1e-pd-fix.git
cd x1e-pd-fix
make

Install

IMPORTANT: A full reboot is REQUIRED after installation. The PD charging parameters must be configured during a fresh boot — the firmware ignores them if set after the PD session is already established. Hot-reloading the module with modprobe -r && modprobe will NOT work. You must reboot (or fully power off and back on) for the fix to take effect.

# Backup original module
sudo cp /lib/modules/$(uname -r)/kernel/drivers/power/supply/qcom_battmgr.ko.zst \
       /lib/modules/$(uname -r)/kernel/drivers/power/supply/qcom_battmgr.ko.zst.bak

# Install patched module
sudo zstd qcom_battmgr.ko \
     -o /lib/modules/$(uname -r)/kernel/drivers/power/supply/qcom_battmgr.ko.zst --force

# Update module dependencies and initramfs
sudo depmod -a
sudo update-initramfs -u

# REBOOT IS REQUIRED — hot-reload will NOT work
sudo reboot

Verify

# Check patched module loaded
cat /sys/module/qcom_battmgr/parameters/pd_current_limit_ua
# Should show: 5000000

# Check charging power
cat /sys/class/power_supply/qcom-battmgr-bat/power_now
# Should show ~30000000-40000000 (30-40W)

# Check USB type
grep -o '\[.*\]' /sys/class/power_supply/ucsi-source-psy-pmic_glink.ucsi.*/usb_type
# Should show: [PD]

Revert

sudo cp /lib/modules/$(uname -r)/kernel/drivers/power/supply/qcom_battmgr.ko.zst.bak \
       /lib/modules/$(uname -r)/kernel/drivers/power/supply/qcom_battmgr.ko.zst
sudo depmod -a
sudo update-initramfs -u
sudo reboot

Module Parameters

Parameter Default Description
pd_current_limit_ua 5000000 (5A) USB PD input current limit in microamps. The firmware clamps to the actual PD contract. Set to 0 to disable automatic PD configuration.

Adjust at runtime:

echo 3000000 | sudo tee /sys/module/qcom_battmgr/parameters/pd_current_limit_ua

Or at boot via kernel cmdline:

qcom_battmgr.pd_current_limit_ua=3000000

Technical Details

Architecture

The Qualcomm X1E80100 SoC communicates with its PMIC (including the SMB2360 charger IC) through PMIC GLINK — a message-passing interface over shared memory. The qcom_battmgr driver sends requests and receives responses through this channel.

┌─────────┐    GLINK     ┌──────────┐    SPMI    ┌─────────┐
│  Linux   │◄───────────►│   PMIC   │◄──────────►│ SMB2360 │
│ battmgr  │  messages   │ Firmware │  registers  │ Charger │
└─────────┘              └──────────┘             └─────────┘
                                                       ▲
                                                       │ USB PD
                                                  ┌────┴────┐
                                                  │ Charger  │
                                                  │ (100W)   │
                                                  └──────────┘

What the patch changes

The upstream driver treats X1E80100 identically to SC8280XP, which only reads battery status notifications containing a simple charging_source field (AC=1, USB=2, Wireless=3). It never queries or sets individual USB properties.

This patch:

  • Adds QCOM_BATTMGR_X1E80100 as a distinct variant
  • Routes USB/WLS property responses to the SM8350 callback (which handles individual property GET/SET)
  • Routes battery status responses to the SC8280XP callback (which handles bulk notifications)
  • On USB charger detection, sends firmware commands to configure PD charging parameters
  • Creates an X1E80100-specific USB power supply descriptor with full property support

GLINK commands sent on charger detect

Command Property Value Purpose
USB_PROPERTY_SET (0x33) USB_ADAP_TYPE (7) 14 (PD) Reclassify charger as PD
USB_PROPERTY_SET (0x33) USB_TYPE (6) 6 (PD) Set USB type to PD
USB_PROPERTY_SET (0x33) USB_CURR_MAX (4) 5000000 Request 5A max current
USB_PROPERTY_SET (0x33) USB_INPUT_CURR_LIMIT (5) 5000000 Set input current limit to 5A
USB_PROPERTY_SET (0x33) USB_VOLT_MAX (2) 20000000 Set max voltage to 20V

Limitations

  • Reboot required: The PD charging parameters must be configured during a fresh boot. The firmware locks its charger classification early in the PD session and ignores changes made after that. Hot-reloading the module with modprobe -r && modprobe will NOT work — you must do a full reboot (or power off/on). This is the single most important thing to know about this fix.
  • Kernel updates: The module must be rebuilt after kernel updates. Consider using DKMS for automation.

Files

File Description
qcom_battmgr.c Patched driver source
qcom_battmgr.c.ubuntu_orig Unmodified Ubuntu 6.17.0-12 source
x1e80100-usb-pd-charging-v4.patch Unified diff
Makefile Out-of-tree module build

Contributing

If you test this on a different X1E80100 laptop, please open an issue with:

  • Laptop model
  • Charger wattage
  • power_now before and after
  • Kernel version
  • Output of ./check-charging.sh (in the scripts/ directory)

License

GPL-2.0-only (same as the Linux kernel)

About

Fix slow USB-C PD charging (~12W→60W) on Snapdragon X Elite (X1E80100) Linux laptops — ASUS Vivobook S Plus, Dell Latitude 7455, Lenovo ThinkPad T14s Gen 6, etc.

Topics

aarch64arm64asus-vivobookbatterycharging-fixdell-latitudekernel-modulelenovo-thinkpadlinux-kernelpmic-glinkpower-deliveryqcom-battmgrqualcommsnapdragon-x-elitesnapdragon-x-plusubuntuusb-pdx1e80100

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