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

From	Pali Rohár <pali.rohar@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for loading NVS calibration data
Date	2017-05-17 15:00 +0200
Message-ID	<tI6Ix-3ck-7@gated-at.bofh.it> (permalink)
References	<tHxrr-6b0-5@gated-at.bofh.it> <tHxrr-6b0-3@gated-at.bofh.it> <tI5Wa-2Uc-9@gated-at.bofh.it>
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On Wednesday 17 May 2017 14:06:06 Johannes Berg wrote:
> On Tue, 2017-05-16 at 01:13 +0200, Luis R. Rodriguez wrote:
> > > > Now for N900 case there is a similar scenario
> > > > alhtough it has additional requirement to go to user-space due to
> > > > need to use a proprietary library to obtain the NVS calibration
> > > > data. My thought: Why should firmware_class care?
> > 
> > Agreed.
> 
> In fact, why should the *driver* care either? IOW - why should
> "request_firmware_prefer_user()" even exist?

There are default/example NVS data, which are stored in /lib/firmware
and installed by linux-firmware package. Those example calibration data
should not be used for real usage, but Pavel told us that on N900 they
are enough for working WIFI connection. They does not contain valid MAC
address, so kernel should generate some (random?).

So kernel driver should get NVS calibration data from userspace (which
know how where to get or how to prepare them) and in case userspace do
not have it, then we can try fallback to those example data (as people
reported us they can be useful instead of non-working WIFI).

And that fallback is working by direct firmware loading from kernel.

-- 
Pali Rohár
pali.rohar@gmail.com

Thread

Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data "Luis R. Rodriguez" <mcgrof@kernel.org> - 2017-05-16 01:20 +0200
  Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-05-16 10:50 +0200
    Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data "Luis R. Rodriguez" <mcgrof@kernel.org> - 2017-05-17 02:00 +0200
  Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data Johannes Berg <johannes@sipsolutions.net> - 2017-05-17 14:10 +0200
    Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data Pali Rohár <pali.rohar@gmail.com> - 2017-05-17 15:00 +0200
      Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data Johannes Berg <johannes@sipsolutions.net> - 2017-05-17 15:10 +0200
        Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data Pali Rohár <pali.rohar@gmail.com> - 2017-05-17 15:30 +0200
          Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data Johannes Berg <johannes@sipsolutions.net> - 2017-05-17 15:30 +0200
      Re: [PATCH 2/6] wl1251: Use request_firmware_prefer_user() for  loading NVS calibration data Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-05-18 02:10 +0200

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