Re: TCPCI driver issue

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Hi Steve,

On Wed, Sep 07, 2016 at 10:00:28PM -0400, Steve Schefter wrote:
> Hi Heikki.
> 
> I'm seeing an issue with the USB-C TCPCI driver.  On startup, I get a panic
> with the following error and stack dump.
> 
> Unable to handle kernel NULL pointer dereference at virtual address 0000002c
> 
> [<ffffffc0006e88a8>] tcpm_register_port+0x228/0x3b0
> [<ffffffc0006ea4f8>] tcpci_probe+0x1c8/0x1fc
> [<ffffffc000718260>] i2c_device_probe+0x12c/0x160
> 
> The problem seems to stem from the fact that tcpci->tcpc.config is not
> initialized in the TCPCI driver.  It is NULL due to tcpci being allocated
> using devm_kzalloc().  This causes a problem when tcpm_register_port()
> attempts to access port->tcpc->config->type.
> 
> Am I missing something?  I understand that this is a work in progress, but
> it looks like this should happen for everyone.  Some I'm wondering if I'm
> missing something dumb.

I believe you are trying Guenter's (CCd) Type-C Port Manager series.
He is the correct best person to answer questions about that. But that
series is RFC, so you can't really expect everything to be in place.
It is more like proof of concept at this point.

But we probable need to talk about how to extract the platform
specific details needed for the config in any case (and also what
exactly is needed) at one point. I think we can get all of them with
device properties regardless of the system (ACPI/DT/whatever), so
we would just need to agree on the what the properties are.

Also adding the list.


Thanks,

-- 
heikki
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