linux-kernel - Re: [PATCH] thunderbolt: icm: Remove Apple check for Alpine Ridge

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Message-ID: <CAAd53p6uJ_LRtLycay=bQG1TsnWeDcKx_b6ZK650-m91vMHWAg@mail.gmail.com>
Date:   Mon, 7 Aug 2017 16:00:06 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, andreas.noever@...il.com,
        michael.jamet@...el.com, yehezkel.bernat@...el.com
Subject: Re: [PATCH] thunderbolt: icm: Remove Apple check for Alpine Ridge

On Mon, Aug 7, 2017 at 3:51 PM, Mika Westerberg
<mika.westerberg@...ux.intel.com> wrote:
> At this point we should find out that the ICM is already running and the
> function never calls pci2cio_write().

I guess you mean this code section:

        /* Check if the ICM firmware is already running */
        val = ioread32(nhi->iobase + REG_FW_STS);
        if (val & REG_FW_STS_ICM_EN)
                return 0;

>
> The reason why it is not happening needs to be resolved.
>
>>       pcie2cio_write()
>>         pci_write_config_dword(pdev, vnd_cap + PCIE2CIO_WRDATA, data);
>>
>> > Is there an actual issue you are trying to solve here?
>>
>> Yes, please take a look at [1].
>>
>> Although both the patch I sent and the diff above still failed to
>> probe the device
>> But there are no more NULL pointer dereference.
>>
>> [1]  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1708043/comments/11
>
> I would like to understand what the actual problem is here because in
> normal cases we should not end up starting ICM firmware in the first
> place.
>
> So no, let's not fix it like this until we know the root cause.
>
> I'll be participating the discussion on the above bug in hopes we could
> figure out the root cause.

Thanks for the information and explanation.