Hello Sebastian，


At 2026-02-04 02:41:26, "Sebastian Reichel" [off-list ref] wrote:

As there are some issues with the DisplayPort support, I went
though Rockchip's BSP kernel tree and looked for fixes. I found
two small changes for the initial register setup, which do not
help with the DP issue but seem sensible in general. Afterwards
I added one more fix, which corrects an issue that effectively
results in USB-C adapters with combined USB3+DP capabilities
not being able to use the DP part.

Afterwards I added one more patch adding single-lane DP support
(found in Rockchip BSP kernel) and a couple of cleanups from my
side. These are logically independent from the fixes, but I put
all together in a single series because they need to be applied
in the right order to avoid conflicts.

Signed-off-by: Sebastian Reichel <redacted>
---
Frank Wang (1):
     phy: rockchip: usbdp: Amend SSC modulation deviation

Sebastian Reichel (4):
     phy: rockchip: usbdp: Add missing mode_change update
     phy: rockchip: usbdp: Rename DP lane functions
     phy: rockchip: usbdp: Use FIELD_PREP_WM16_CONST
     phy: rockchip: usbdp: Cleanup DP lane selection function

William Wu (1):
     phy: rockchip: usbdp: Fix LFPS detect threshold control

Zhang Yubing (1):
     phy: rockchip: usbdp: Support single-lane DP

drivers/phy/rockchip/phy-rockchip-usbdp.c | 114 +++++++++++++-----------------
1 file changed, 48 insertions(+), 66 deletions(-)

After applying this series of patches, the hub that previously couldn’t recognize Alt Mode can now detect it and work properly, 
but it also triggers a USB-related SERR — did I miss something？


[    2.639842][  T244] 8021q: adding VLAN 0 to HW filter on device eth1
[    3.872936][   T23] usb 3-1: new high-speed USB device number 2 using xhci-hcd
[    4.011232][   T23] usb 3-1: New USB device found, idVendor=2109, idProduct=2817, bcdDevice= 5.54
[    4.012102][   T23] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[    4.012908][   T23] usb 3-1: Product: USB2.0 Hub             
[    4.013469][   T23] usb 3-1: Manufacturer: VIA Labs, Inc.         
[    4.014064][   T23] usb 3-1: SerialNumber: 000000000
[    4.071154][   T23] hub 3-1:1.0: USB hub found
[    4.071876][   T23] hub 3-1:1.0: 5 ports detected
[    4.385554][    C1] SError Interrupt on CPU1, code 0x00000000bf000002 -- SError
[    4.385592][    C1] CPU: 1 UID: 0 PID: 96 Comm: kworker/1:1 Tainted: G   M                6.19.0-rc4+ #223 PREEMPT 
[    4.385623][    C1] Tainted: [M]=MACHINE_CHECK
[    4.385632][    C1] Hardware name: ArmSoM Sige5 (DT)
[    4.385644][    C1] Workqueue: usb_hub_wq hub_event
[    4.385680][    C1] pstate: 000000c5 (nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[    4.385701][    C1] pc : el1_abort+0x34/0x68
[    4.385728][    C1] lr : el1_abort+0x24/0x68
[    4.385749][    C1] sp : ffff8000833a36c0
[    4.385758][    C1] x29: ffff8000833a36c0 x28: ffff0000c3568000 x27: ffff0000c3d70c48
[    4.385792][    C1] x26: ffff0000c13c8d78 x25: 0000000000000004 x24: 0000000000000001
[    4.385823][    C1] x23: 00000000600000c5 x22: ffff800084088430 x21: 0000000096000210
[    4.385854][    C1] x20: 0000000000000000 x19: ffff8000833a3700 x18: 00000000ffffffff
[    4.385885][    C1] x17: ffff800083179000 x16: ffffffffffffffff x15: ffff0000c11ba128
[    4.385916][    C1] x14: 0000000000000376 x13: 0000000000000376 x12: 0000000000000000
[    4.385946][    C1] x11: 00000000000000c0 x10: 0000000000000af0 x9 : 0000000000002303
[    4.385976][    C1] x8 : ffff8000833a3740 x7 : ffff8000833a3830 x6 : ffff8000833a3800
[    4.386006][    C1] x5 : ffff8000833a3780 x4 : ffff8000833a4000 x3 : ffff8000812c986c
[    4.386037][    C1] x2 : ffff8000812c986c x1 : 00000000000000c0 x0 : 0000000000000000
[    4.386071][    C1] Kernel panic - not syncing: Asynchronous SError Interrupt
[    4.386085][    C1] CPU: 1 UID: 0 PID: 96 Comm: kworker/1:1 Tainted: G   M                6.19.0-rc4+ #223 PREEMPT 
[    4.386113][    C1] Tainted: [M]=MACHINE_CHECK
[    4.386121][    C1] Hardware name: ArmSoM Sige5 (DT)
[    4.386131][    C1] Workqueue: usb_hub_wq hub_event
[    4.386156][    C1] Call trace:
[    4.386164][    C1]  show_stack+0x18/0x24 (C)
[    4.386202][    C1]  dump_stack_lvl+0x60/0x80
[    4.386236][    C1]  dump_stack+0x18/0x24
[    4.386266][    C1]  vpanic+0xf8/0x2ac
[    4.386290][    C1]  trace_suspend_resume+0x0/0x7c
[    4.386314][    C1]  add_taint+0x0/0xbc
[    4.386342][    C1]  arm64_serror_panic+0x70/0x80
[    4.386364][    C1]  do_serror+0x3c/0x74
[    4.386384][    C1]  el1h_64_error_handler+0x34/0x50
[    4.386414][    C1]  el1h_64_error+0x6c/0x70
[    4.386436][    C1]  el1_abort+0x34/0x68 (P)
[    4.386462][    C1]  el1h_64_sync_handler+0x50/0xac
[    4.386490][    C1]  el1h_64_sync+0x6c/0x70
[    4.386511][    C1]  xhci_portsc_readl+0x4/0x1c (P)
[    4.386538][    C1]  usb_hcd_submit_urb+0x48c/0xa3c
[    4.386565][    C1]  usb_submit_urb+0x1e0/0x650
[    4.386593][    C1]  usb_start_wait_urb+0x74/0x17c
[    4.386621][    C1]  usb_control_msg+0xc4/0x140
[    4.386648][    C1]  hub_port_reset+0x118/0x9c0
[    4.386672][    C1]  hub_port_init+0xb4/0xd84
[    4.386694][    C1]  hub_event+0x10e4/0x1a5c
[    4.386718][    C1]  process_one_work+0x16c/0x3d4
[    4.386752][    C1]  worker_thread+0x2c4/0x3f4
[    4.386773][    C1]  kthread+0x130/0x1ec
[    4.386803][    C1]  ret_from_fork+0x10/0x20
[    4.386829][    C1] SMP: stopping secondary CPUs
[    4.386854][    C1] Kernel Offset: disabled
[    4.386861][    C1] CPU features: 0x200000,10410001,00008000,0400420b
[    4.386876][    C1] Memory Limit: none
[    4.414238][    C1] ---[ end Kernel panic - not syncing: Asynchronous SError Interrupt ]---

---
base-commit: 18f7fcd5e69a04df57b563360b88be72471d6b62
change-id: 20260203-rockchip-usbdp-cleanup-5b59dfb561a3

Best regards,
-- 
Sebastian Reichel [off-list ref]


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