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

On 3-1-2017 18:59, Luis R. Rodriguez wrote:

On Mon, Dec 26, 2016 at 05:35:59PM +0100, Pavel Machek wrote:

quoted

Right question is "should we solve it without user-space help"?

Answer is no, too. Way too complex. Yes, it would be nice if hardware
was designed in such a way that getting calibration data from kernel
is easy, and if you design hardware, please design it like that. But
N900 is not designed like that and getting the calibration through
userspace looks like only reasonable solution.

Arend seems to have a better alternative in mind possible for other
devices which *can* probably pull of doing this easily and nicely,
given the nasty history of the usermode helper crap we should not
in any way discourage such efforts.

Arend -- please look at the firmware cache, it not a hash but a hash
table for an O(1) lookups would be a welcomed change, then it could
be repurposed for what you describe, I think the only difference is
you'd perhaps want a custom driver hook to fetch the calibration data
so the driver does whatever it needs.

Hi Luis,

I let my idea catch dust on the shelf for a while. Actually had a couple
of patches ready, but did get around testing them. So I wanted to rebase
them on your linux-next tree. I bumped into the umh lock thing and was
wondering why direct filesystem access was under that lock as well. In
your tree I noticed a fix for that. The more reason to base my work on
top of your firmware_class changes. Now my question is what is the best
branch to choose, because you have a "few" in that repo to choose from ;-)

Regards,
Arend