[Bug 2143685] Re: USB-C DisplayPort unstable on Dell Pro Max 14 (Arrow Lake-P 7d51) - xe.force_probe fails, typec_ucsi WARNING

** Tags added: kernel-daily-bug

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Title:
USB-C DisplayPort unstable on Dell Pro Max 14 (Arrow Lake-P 7d51) -
xe.force_probe fails, typec_ucsi WARNING

Status in linux package in Ubuntu:
New

Bug description:
# Bug: USB-C DisplayPort alt-mode unstable on Dell Pro Max 14 (Arrow
Lake-P) with xe.force_probe

## Summary

On Dell Pro Max 14 MC14250 with Intel Arrow Lake-P GPU [8086:7d51],
USB-C DisplayPort alt-mode is unstable when using i915 driver on
kernel 6.17.0-14. External monitors connected via USB-C randomly
disconnect and reconnect. Kernel WARNING in
typec_altmode_update_active() triggers repeatedly during cable
plug/unplug events.

Additionally, GRUB was configured with `i915.force_probe=!7d51
xe.force_probe=7d51` (possibly set by an Ubuntu update or installer),
which completely blocked i915 from probing the GPU. The xe driver
failed to load, leaving the system with no functional GPU driver —
only a basic framebuffer, no DP alt-mode, and no external monitors.
Removing these parameters restored i915 functionality.

## System Information

- **Laptop**: Dell Pro Max 14 MC14250
- **OS**: Ubuntu 25.10 (Questing Quokka)
- **Kernel**: 6.17.0-14-generic #14-Ubuntu SMP PREEMPT_DYNAMIC
- **GPU**: Intel Arrow Lake-P [Intel Graphics] [8086:7d51] (rev 03)
- **BIOS**: Dell 1.10.1 (2025-12-11)
- **CPU Microcode**: 0x11b (updated 2026-03-05)
- **Monitors**: 2x 5K (5120x2880) via USB-C, 1x laptop eDP (3072x1920)

## Issues

### Issue 1: xe.force_probe blocks GPU entirely

With `i915.force_probe=!7d51 xe.force_probe=7d51` in GRUB_CMDLINE_LINUX_DEFAULT:
- i915 logs: `I915 probe blocked for Device ID 7d51`
- xe driver does not load (not visible in lsmod)
- GPU falls back to basic framebuffer
- No USB-C DisplayPort alt-mode — external monitors do not work
- Only eDP (laptop screen) works at reduced capability

**Workaround**: Remove both parameters, use plain `quiet splash`

### Issue 2: typec_ucsi WARNING on USB-C hotplug

After restoring i915, external monitors work but are unstable:
- Disconnecting/reconnecting USB-C cables triggers kernel WARNING
- `typec_displayport port1-partner.0: failed to enter mode: -107`
- Multiple WARNINGs at `drivers/usb/typec/class.c:311 typec_altmode_update_active`
- Race condition in `ucsi_unregister_altmodes` / `ucsi_handle_connector_change`
- Monitors sometimes fail to re-establish DP alt-mode after cable movement

### Kernel log excerpts

```
kernel: typec_displayport port1-partner.0: failed to enter mode: -107

kernel: WARNING: CPU: 5 PID: 12 at drivers/usb/typec/class.c:311 typec_altmode_update_active+0x101/0x110 [typec]
kernel: Workqueue: USBC000:00-con2 ucsi_poll_worker [typec_ucsi]
kernel: RIP: 0010:typec_altmode_update_active+0x101/0x110 [typec]

kernel: Workqueue: events ucsi_handle_connector_change [typec_ucsi]
kernel: typec_unregister_altmode+0x3b/0x50 [typec]
kernel: ucsi_unregister_altmodes+0x53/0xb0 [typec_ucsi]
kernel: ucsi_unregister_partner+0x89/0x150 [typec_ucsi]
```

## Steps to Reproduce

1. Boot Dell Pro Max 14 MC14250 with Ubuntu 25.10, kernel 6.17.0-14
2. Connect two 5K monitors via USB-C
3. Observe: monitors may or may not initialize
4. Disconnect and reconnect USB-C cable → kernel WARNING, monitor may not return

## Expected Behavior

- xe driver should work if force_probe is set, OR force_probe should not be set by default
- USB-C DP alt-mode should survive cable reconnection without kernel warnings

## Workaround

Remove `i915.force_probe=!7d51 xe.force_probe=7d51` from GRUB config:
```bash
sudo sed -i 's/quiet splash i915.force_probe=!7d51 xe.force_probe=7d51/quiet splash/' /etc/default/grub
sudo update-grub
```

## Available kernels for bisect

- 6.17.0-12-generic (installed, not yet tested for this issue)
- 6.17.0-14-generic (current, affected)

ProblemType: Bug
DistroRelease: Ubuntu 25.10
Package: linux-image-6.17.0-14-generic 6.17.0-14.14
ProcVersionSignature: Ubuntu 6.17.0-14.14-generic 6.17.9
Uname: Linux 6.17.0-14-generic x86_64
ApportVersion: 2.33.1-0ubuntu3
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: subone 3494 F.... pipewire
subone 3533 F.... wireplumber
/dev/snd/seq: subone 3494 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Mar 9 01:42:53 2026
InstallationDate: Installed on 2026-01-15 (52 days ago)
InstallationMedia: Ubuntu 25.10 "Questing Quokka" - Release amd64 (20251007)
MachineType: Dell Inc. Dell Pro Max 14 MC14250
ProcEnviron:
LANG=pl_PL.UTF-8
PATH=(custom, no user)
SHELL=/usr/bin/zsh
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.17.0-14-generic root=UUID=80e678ad-e34e-4c24-bd1a-4f5f157f2400 ro quiet splash crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M vt.handoff=7
RelatedPackageVersions:
firmware-sof N/A
linux-firmware 20250901.git993ff19b-0ubuntu1.9
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/11/2025
dmi.bios.release: 1.10
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.10.1
dmi.board.name: 0YJFPY
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.ec.firmware.release: 1.22
dmi.modalias: dmi:bvnDellInc.:bvr1.10.1:bd12/11/2025:br1.10:efr1.22:svnDellInc.:pnDellProMax14MC14250:pvr:rvnDellInc.:rn0YJFPY:rvrA00:cvnDellInc.:ct10:cvr:sku0CF0:
dmi.product.family: Dell Pro Max Laptops
dmi.product.name: Dell Pro Max 14 MC14250
dmi.product.sku: 0CF0
dmi.sys.vendor: Dell Inc.

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