Question regarding using Driver Component Framework (crashing kernel)

[Mika Westerberg]

Hi,

Don't you have like a serial port that you can turn on early debugging
to see where it blows up? If not that then at least the USB 3 DbC.

On Tue, Mar 22, 2022 at 12:01:15PM -0700, Won Chung wrote:
> Hi,
> 
> I am not sure if this is the correct mailing list to ask about Driver
> Component Framework, so if I am mistaken, I would appreciate it if
> anyone can correct me to the right direction.
> 
> I have a quick question on using driver component framework and a
> strange crash I am seeing when I use component framework.
> 
> There is then component framework currently being used for typec
> connector, as below
> https://elixir.bootlin.com/linux/latest/source/drivers/usb/typec/port-mapper.c
> We add component for usb port to link it with typec connector, as below
> https://elixir.bootlin.com/linux/latest/source/drivers/usb/core/port.c#L622
> https://elixir.bootlin.com/linux/latest/source/drivers/usb/core/port.c#L568
> 
> We are trying to do something similar for usb4 port, add component to
> link to typec connector.
> I have attached a patch to this email for reference.
> However, this change causes a crash in kernel for some devices.
> The crash is too early in the kernel that it is not giving any logs at all.
> This crash is somehow fixed when we change usb4 config from =y
> (built-in) to =m (loadable module).
> So, I am curious if there are some aspects in the component framework
> that depends on whether the device with a component added is a
> built-in or loadable module.
> 
> If anyone has seen a similar issue or have an idea on what is
> happening, can you share your thoughts on what might be the issue and
> how the crash can be avoided?
> Thank you very much!
> 
> Won