linux-kernel - Re: [PATCH RFC] thunderbolt: Re-add DP resources on resume

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Message-ID: <a3dd4fc5-4312-4c06-a6d7-645ae0f7b68b@kylinos.cn>
Date: Fri, 19 Sep 2025 15:24:20 +0800
From: 李佳怡 <lijiayi@...inos.cn>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC] thunderbolt: Re-add DP resources on resume



在 2025/9/19 00:43, Mika Westerberg 写道:
> On Thu, Sep 18, 2025 at 06:20:59PM +0200, Mika Westerberg wrote:
>> Hi,
>>
>> On Thu, Sep 18, 2025 at 04:34:31PM +0800, 李佳怡 wrote:
>>>
>>>
>>> 在 2025/9/17 20:50, Mika Westerberg 写道:
>>>> On Wed, Sep 17, 2025 at 06:12:31PM +0800, 李佳怡 wrote:
>>>>>
>>>>> As requested, I've attached the complete dmesg output (from boot to after
>>>>> resume) reproducing the issue.
>>>>>
>>>>> Testing Methodology:
>>>>> 1. Start with the Targus Thunderbolt dock already connected to the system
>>>>> 2. Enter S3 suspend (sleep) with no DP monitor connected to the dock
>>>>> 3. Resume from S3
>>>>> 4. After the system has fully resumed, connect the DP monitor to the dock
>>>>
>>>> Thanks! It is badly line wrapped. I wonder if you can just attach it?
>>>> Anyways I found some unexpected things there:
>>>>
>>>>> [    8.647850] With USB4 patch v1.0.0
>>>>
>>>> What is this? ;-)
>>>
>>> Thanks for your help!
>>>
>>> This is a self-compiled kernel based on version 5.4 with backported
>>> Thunderbolt drivers. I will also attach the kernel log from a build using
>>> the linux-6.6.y branch of the community linux-stable repository.
>>
>> Okay but I really suggest using more recent kernel. 6.16 is current stable
>> so that would be good.
>>
>>>>> [    8.647860] ACPI: bus type thunderbolt registered
>>>>> [    8.664660] [7] nhi_probe:1326: thunderbolt 0000:2c:00.0: total paths: 21
>>>>> [    8.665209] [7] tb_ring_alloc:586: thunderbolt 0000:2c:00.0: allocating
>>>>> TX ring 0 of size 10
>>>>> [    8.665243] [7] tb_ring_alloc:586: thunderbolt 0000:2c:00.0: allocating
>>>>> RX ring 0 of size 10
>>>>> [    8.665267] [7] tb_ctl_alloc:665: thunderbolt 0000:2c:00.0: control
>>>>> channel created
>>>>> [    8.665272] [7] icm_probe:2549: thunderbolt 0000:2c:00.0: ICM not
>>>>> supported on this controller
>>>>> [    8.665285] [7] tb_ring_free:840: thunderbolt 0000:2c:00.0: freeing RX
>>>>> ring 0
>>>>> [    8.665294] [7] tb_ring_free:840: thunderbolt 0000:2c:00.0: freeing TX
>>>>> ring 0
>>>>
>>>> What is this?
>>>>
>>>> Is this Intel TB/USB4 controller or something else? All USB4 compliant
>>>> controllers should go directly to tb.c as that's the part dealing with
>>>> software connection manager. The above looks like it tries first with the
>>>> firmware connection manager and that should not happen outside of Intel
>>>> Thunderbolt 3 hosts.
>>>
>>> Yes, there is a mistake. I discovered that during the USB4_NATIVE_CONTROL
>>> negotiation in the firmware, an OSC_CAPABILITIES_MASK_ERROR bit was being
>>> set incorrectly, which should not have happened.
>>>
>>> The log I will attach next has been modified to fix this issue.
>>
>> [..]
>>
>>> [    0.498976] [1] tb_switch_reset:1666: thunderbolt 0000:2c:00.0: 0: resetting
>>> [    0.533329] [1] tb_add_dp_resources:217: thunderbolt 0000:2c:00.0: 0:10: DP IN resource available
>>> [    0.533959] [1] tb_add_dp_resources:217: thunderbolt 0000:2c:00.0: 0:11: DP IN resource available
>>
>> The DP IN resources were added here.
>>
>> [..]
>>
>>> [   19.035726] [171] tb_switch_set_wake:3445: thunderbolt 0000:2c:00.0: 0: enabling wakeup: 0x3f
>>> [   19.037401] [171] tb_ring_stop:768: thunderbolt 0000:2c:00.0: stopping RX ring 0
>>> [   19.037412] [171] ring_interrupt_active:141: thunderbolt 0000:2c:00.0: disabling interrupt at register 0x38200 bit 21 (0x200001 -> 0x1)
>>> [   19.037439] [171] tb_ring_stop:768: thunderbolt 0000:2c:00.0: stopping TX ring 0
>>> [   19.037449] [171] ring_interrupt_active:141: thunderbolt 0000:2c:00.0: disabling interrupt at register 0x38200 bit 0 (0x1 -> 0x0)
>>> [   19.037463] [171] tb_ctl_stop:733: thunderbolt 0000:2c:00.0: control channel stopped
>>
>> Runtime suspend.
>>
>> (and a couple more)
>>
>>> [  266.399800] [3870] tb_ctl_start:703: thunderbolt 0000:2c:00.0: control channel starting...
>>> [  266.399808] [3870] tb_ring_start:693: thunderbolt 0000:2c:00.0: starting TX ring 0
>>> [  266.399821] [3870] ring_interrupt_active:141: thunderbolt 0000:2c:00.0: enabling interrupt at register 0x38200 bit 0 (0x0 -> 0x1)
>>> [  266.399826] [3870] tb_ring_start:693: thunderbolt 0000:2c:00.0: starting RX ring 0
>>> [  266.399837] [3870] ring_interrupt_active:141: thunderbolt 0000:2c:00.0: enabling interrupt at register 0x38200 bit 21 (0x1 -> 0x200001)
>>> [  266.399848] [3870] tb_switch_resume:3478: thunderbolt 0000:2c:00.0: 0: resuming switch
>>> [  266.399852] [3870] tb_switch_configure:2590: thunderbolt 0000:2c:00.0: restoring Switch at 0x0 (depth: 0, up port: 5)
>>> [  266.400032] [3870] tb_switch_set_wake:3447: thunderbolt 0000:2c:00.0: 0: disabling wakeup
>>
>> Around this time you should see the hotplug events coming to the DP IN
>> adapters. But there is none.
>>
>> There is a bit in the DP adapter config space (DHP) that can be used to
>> disable this but the spec says it defaults to 0. Anyways I suggest to check
>> that (and also the Plugged bit). You can dump these using tbtools [1]. Let
>> me know if you want help with that.
> 
> Nevermind about the Plugged bit, that's not applicable here.
> 
> Here's how to dump the DHP bit. This is from Intel host:
> 
> # tbdump -vv -r 0 -N 1 -a 5 ADP_CS_5
> 0x0005 0x00004809 0b00000000 00000000 01001000 00001001 ..H. ADP_CS_5
>    [00:06]        0x9 Max Input HopID
>    [11:17]        0x9 Max Output HopID
>    [22:28]        0x0 Link Credits Allocated
>    [29:29]        0x0 HEC Error Enable (HEE)
>    [30:30]        0x0 Flow Control Error Enable (FCEE)
>    [31:31]        0x0 Disable Hot Plug Events (DHP)

Thank you for your help. As you suggested, I tried kernel 6.16, but the 
issue still persists.

The logs and device vendor information are included in the attachment. I 
also ran the tbdump command, and the result shows the DHP bit is set to 
0. Does this indicate there might still be other issues?

# tbdump -vv -r 0 -N 1  -a 5 ADP_CS_5
0x0005 0x0000d814 0b00000000 00000000 11011000 00010100 .... ADP_CS_5
   [00:06]       0x14 Max Input HopID
   [11:17]       0x1b Max Output HopID
   [22:28]        0x0 Link Credits Allocated
   [29:29]        0x0 HEC Error Enable (HEE)
   [30:30]        0x0 Flow Control Error Enable (FCEE)
   [31:31]        0x0 Disable Hot Plug Events (DHP)
View attachment "thunderbolt-6.16.txt" of type "text/plain" (121672 bytes)

View attachment "lspci.txt" of type "text/plain" (3574 bytes)