[RFC] ath10k: silence firmware file probing warnings

[Michal Kazior]

On 20 January 2017 at 13:51, Kalle Valo <kvalo at qca.qualcomm.com> wrote:
> Michal Kazior <michal.kazior at tieto.com> wrote:
>> Firmware files are versioned to prevent older
>> driver instances to load unsupported firmware
>> blobs. This is reflected with a fallback logic
>> which attempts to load several firmware files.
>>
>> This however produced a lot of unnecessary
>> warnings sometimes confusing users and leading
>> them to rename firmware files making things even
>> more confusing.
>>
>> Hence use request_firmware_direct() which does not
>> produce extra warnings. This shouldn't really
>> break anything because most modern systems don't
>> rely on udev/hotplug helpers to load firmware
>> files anymore.
>>
>> Signed-off-by: Michal Kazior <michal.kazior at tieto.com>
>
> This ended into a rather long discussion, see the full thread from the patchwork link
> below, but I'll try to summarise it here:
>
> * Nobody stepped up and mentioned that they need/use the user fallback helper with ath10k.
>
> * Felix confirmed that LEDE creates the calibration file before loading ath10k
>   so this should not break LEDE.
>
> * This also fixes a 60 second delay per _each_ unexistent firmware/calibration
>   file with distros which have CONFIG_FW_LOADER_USER_HELPER_FALLBACK enabled,
>   RHEL being a notable example. Using ath10k with firmware-2.bin this might
>   end up into a five minute delay in boot.
>
> * Luis is working on new drvdata interface for kernel, but that's not merged yet.
>
> Based on this I think the right approach is to apply this patch. Any concerns?
>
> While writing this I started to suspect is it just by accident that
> request_firmware_direct() does not print any error messages and
> request_firmware() again does print those? Let's hope nobody decides to change
> that.  And at least Luis' drvdata interface has a documented 'optional' flag,
> so we can always switch to using that (once it's merged):
>
> * struct drvdata_req_params - driver data request parameters
> * @optional: if true it is not a hard requirement by the caller that this
> *       file be present. An error will not be recorded if the file is not
> *       found.
>
> Michal, do you mind if I'll add more info to the commit log and submit this RFC
> as a proper patch? It still seems to apply and work just fine.

I don't mind :)


Michał