Re: [PATCH 2/6] ath9k: add a quirk to set use_msi automatically

[AceLan Kao]

Hi Daniel,

After applied the 2 commits you mentioned in the email, ath9k works.

https://marc.info/?l=linux-wireless&m=150631274108016&w=2
https://github.com/endlessm/linux/commit/739c7a924db8f4434a9617657

Best regards,
AceLan Kao.

2017-10-05 14:39 GMT+08:00 AceLan Kao <acelan.kao@xxxxxxxxxxxxx>:
> Hi all,
>
> Please drop my patches, Qualcomm is working internally and will submit
> the MSI patch by themselves.
> Thanks.
>
> Hi Daniel,
>
> I'll try your patches tomorrow.
>
> Best regards,
> AceLan Kao.
>
> 2017-10-02 12:21 GMT+08:00 Daniel Drake <drake@xxxxxxxxxxxx>:
>> Hi AceLan,
>>
>> On Thu, Sep 28, 2017 at 4:28 PM, AceLan Kao <acelan.kao@xxxxxxxxxxxxx> wrote:
>>> Hi Daniel,
>>>
>>> I've tried your patch, but it doesn't work for me.
>>> Wifi can scan AP, but can't get connected.
>>
>> Can you please clarify which patch(es) you have tried?
>>
>> This is the base patch which adds the infrastructure to request
>> specific MSI IRQ vectors:
>> https://marc.info/?l=linux-wireless&m=150631274108016&w=2
>>
>> This is the ath9k MSI patch which makes use of that:
>> https://github.com/endlessm/linux/commit/739c7a924db8f4434a9617657
>>
>> If you were already able to use ath9k MSI interrupts without specific
>> consideration for which MSI vector numbers were used, these are the
>> possible explanations that spring to mind:
>>
>> 1. You got lucky and it picked a vector number that is 4-aligned. You
>> can check this in the "lspci -vvv" output. You'll see something like:
>> Capabilities: [50] MSI: Enable+ Count=1/4 Maskable+ 64bit+
>>         Address: 00000000fee0300c  Data: 4142
>> The lower number is the vector number. In my example here 0x42 (66) is
>> not 4-aligned so the failure condition will be hit.
>>
>> 2. You are using interrupt remapping, which I suspect may provide a
>> high likelihood of MSI interrupt vectors being 4-aligned. See if
>> /proc/interrupts shows the IRQ type as IR-PCI-MSI
>> Unfortunately interrupt remapping is not available here,
>> https://lists.linuxfoundation.org/pipermail/iommu/2017-August/023717.html
>>
>> 3. My assumption that all ath9k hardware corrupts the MSI vector
>> number could wrong. However we've seen this on different wifi modules
>> in laptops produced by different OEMs and ODMs, so it seems to be a
>> somewhat widespread problem at least.
>>
>> 4. My assumption that ath9k hardware is corrupting the MSI vector
>> number could be wrong; maybe another component is to blame, could it
>> be a BIOS issue? Admittedly I don't really know how I can debug the
>> layers inbetween seeing the MSI Message Data value disagree with the
>> vector number being handled inside do_IRQ().
>>
>> Daniel