Re: Fwd: USB DBC hang during earlyprintk initialization

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 10/28/25 15:29, Milan Oravec wrote:
> Hello Mathias, here is dmesg output after applying additional patch:
> 
> [Ut okt 28 14:07:39 2025] Linux version 6.17.5-dirty (migo@migoG17)
> (gcc (GCC) 15.2.1 20250813, GNU ld (GNU Binutils) 2.45.0) #59 SMP
> PREEMPT_DYNAMIC Tue Oct 28 11:54:08 CET
>   2025
> [Ut okt 28 14:07:39 2025] Command line: BOOT_IMAGE=/vmlinuz
> root=UUID=584262b6-b020-4e4f-95a3-1db754e28b6c earlyprintk=keep,xdbc1

> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_map_pci_mmio: Failed to
> ioremap xhci-dbc with size 0x100000
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_map_pci_mmio: Retry xhci-dbc
> ioremap with reduced size 0x80000
> [Ut okt 28 14:07:39 2025] ------------[ cut here ]------------
> [Ut okt 28 14:07:39 2025] WARNING: CPU: 0 PID: 0 at
...> [Ut okt 28 14:07:39 2025] ---[ end trace 0000000000000000 ]---
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_map_pci_mmio: Failed to
> ioremap xhci-dbc with size 0x80000
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_map_pci_mmio: Retry xhci-dbc
> ioremap with reduced size 0x40000
> [Ut okt 28 14:07:39 2025] xhci_dbc:early_xdbc_parse_parameter: Looking
> for DbC capability at offset 0x480
> [Ut okt 28 14:07:39 2025] xhci_dbc:early_xdbc_parse_parameter: Looking
> for DbC capability at offset 0x490
> [Ut okt 28 14:07:39 2025] xhci_dbc:early_xdbc_parse_parameter: Looking
> for DbC capability at offset 0x4a0
> [Ut okt 28 14:07:39 2025] xhci_dbc:early_xdbc_parse_parameter: Looking
> for DbC capability at offset 0x4c0
> [Ut okt 28 14:07:39 2025] xhci_dbc:early_xdbc_parse_parameter: Looking
> for DbC capability at offset 0x4e0
> [Ut okt 28 14:07:39 2025] xhci_dbc:early_xdbc_parse_parameter: DbC
> capability found at offset 0x4e0
...> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_early_setup: DCE successfully cleared
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_early_setup: Successfully got
> xdbc table_dma page
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_early_setup: Successfully got
> xdbc out_dma page
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_early_setup: Successfully
> allocated event ring
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_early_setup: Successfully
> allocated in ring
> [Ut okt 28 14:07:39 2025] xhci_dbc:xdbc_early_setup: Successfully
> allocated out ring
> [Ut okt 28 14:07:44 2025] xhci_dbc:xdbc_start: waiting for connection timed out

This is promising, looks like code successfully interacts with hardware.

> [Ut okt 28 14:07:44 2025] xhci_dbc:xdbc_early_setup: Failed to start
> xdbc ret: -110
> [Ut okt 28 14:07:44 2025] xhci_dbc:early_xdbc_setup_hardware: failed
> to setup the connection to host
> [Ut okt 28 14:07:44 2025] Zone ranges:
> [Ut okt 28 14:07:44 2025]   DMA      [mem 0x0000000000001000-0x0000000000ffffff]
> [Ut okt 28 14:07:44 2025]   DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
> [Ut okt 28 14:07:44 2025]   Normal   [mem 0x0000000100000000-0x000000085de7ffff]
> [Ut okt 28 14:07:44 2025]   Device   empty
> [Ut okt 28 14:07:44 2025] Movable zone start for each node
> [Ut okt 28 14:07:44 2025] Early memory node ranges
> 
> I've tested cable afterwards:
> 
> echo enable > /sys/devices/pci0000:00/0000:00:08.1/0000:09:00.4/dbc
> 
> [Ut okt 28 14:12:28 2025] xhci_hcd 0000:09:00.4: DbC connected
> [Ut okt 28 14:12:29 2025] xhci_hcd 0000:09:00.4: DbC configured
> 
> so cable is not the problem here...
> 
> Thank you!

your lspci listed four xHCI controllers:

07:00.0 USB controller: ASMedia Technology Inc. Device 242c (rev 01)
	(prog-if 30 [XHCI])
	Region 0: Memory at fc600000 (64-bit, non-prefetchable) [size=32K]

09:00.3 USB controller: Advanced Micro Devices, Inc. [AMD]
	Raphael/Granite Ridge USB 3.1 xHCI (prog-if 30 [XHCI])
	Region 0: Memory at fc300000 (64-bit, non-prefetchable) [size=1M]

09:00.4 USB controller: Advanced Micro Devices, Inc. [AMD]
	Raphael/Granite Ridge USB 3.1 xHCI (prog-if 30 [XHCI])
	Region 0: Memory at fc200000 (64-bit, non-prefetchable) [size=1M]

0a:00.0 USB controller: Advanced Micro Devices, Inc. [AMD]
         Raphael/Granite Ridge USB 2.0 xHCI (prog-if 30 [XHCI])
         Region 0: Memory at fca00000 (64-bit, non-prefetchable) [size=1M]

Could it be that the cable is connected to xHCI at 09:00.4 while
earlyprintk=keep,xdbc1 refers to different xHCI? possibly the one at 09:00.3?

Does earlyprintk=keep,xdbc2 work? or trying a different usb port?

Thanks
Mathias