Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for loading NVS calibration data

From: Arend Van Spriel
Date: Fri Jan 27 2017 - 07:54:15 EST

On 27-1-2017 13:26, Kalle Valo wrote:
> Pali RohÃr <pali.rohar@xxxxxxxxx> writes:
>> On Friday 27 January 2017 13:49:03 Kalle Valo wrote:
>>> Pali RohÃr <pali.rohar@xxxxxxxxx> writes:
>>>>> So
>>>>> for those other platforms there will be a delay waiting for user-mode
>>>>> helper to fail, before trying to get nvs file from /lib/firmware.
>>>> Yes, there will be. But there is no easy way to fix this problem that
>>>> kernel is trying to use default/example NVS data...
>>> Kernel is doing correctly and requesting NVS data as expected, the
>>> problem here is that linux-firmware claims that the example NVS data is
>>> real calibration data (which it is not). Distros should not use that,
>>> only developers for testing purposes. We should not courage users using
>>> example calibration data.
>>> The simple fix is to rename the NVS file in linux-firmware to something
>>> like wl1251-nvs.bin.example, no need to workaround this in kernel. If
>>> you send a patch to linux-firmware I'm happy to ack that.
>> I agree with rename and fact that default/example data should not be
>> used.
>> But...
>> 1) Kernel should not read device/model specific data from VFS where
>> are stored not-device-specific files preinstalled by linux
>> distributions.
>> And linux distributions are already putting files into VFS and kernel
>> cannot enforce userspace to not do that (as they are already doing it).
> I'm having problems to understand what you are saying here.

This is a personal opinion. I read it as: /lib/firmware can only contain
files for from linux-firmware.

At least the device-specific vs. non-device-specific does not seem to
hold. The firmware files that we have in the linux-firmware repository
are very device-specific. Unless you mean the 'platform' when talking
about 'device'.