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Subject: Re: [PATCH 0/1] add support for enum module parameters
To:     Kalle Valo <kvalo@kernel.org>, Jani Nikula <jani.nikula@intel.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Lucas De Marchi <lucas.demarchi@intel.com>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org
References: <20220414123033.654198-1-jani.nikula@intel.com>
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From:   Ben Greear <greearb@candelatech.com>
Organization: Candela Technologies
Message-ID: <0be3baa1-d4aa-8ab2-173f-085d47497251@candelatech.com>
Date:   Wed, 20 Apr 2022 08:35:30 -0700
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On 4/19/22 10:13 PM, Kalle Valo wrote:
> + linux-wireless, netdev
> 
> Jani Nikula <jani.nikula@intel.com> writes:
> 
>> On Thu, 14 Apr 2022, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
>>> On Thu, Apr 14, 2022 at 03:30:32PM +0300, Jani Nikula wrote:
>>>> Hey, I've sent this before, ages ago, but haven't really followed
>>>> through with it. I still think it would be useful for many scenarios
>>>> where a plain number is a clumsy interface for a module param.
>>>>
>>>> Thoughts?
>>>
>>> We should not be adding new module parameters anyway (they operate on
>>> code, not data/devices), so what would this be used for?
>>
>> I think it's just easier to use names than random values, and this also
>> gives you range check on the input.
>>
>> I also keep telling people not to add new module parameters, but it's
>> not like they're going away anytime soon.
>>
>> If there's a solution to being able to pass device specific debug
>> parameters at probe time, I'm all ears. At least i915 has a bunch of
>> things which can't really be changed after probe, when debugfs for the
>> device is around. Module parameters aren't ideal, but debugfs doesn't
>> work for this.
> 
> Wireless drivers would also desperately need to pass device specific
> parameters at (or before) probe time. And not only debug parameters but
> also configuration parameters, for example firmware memory allocations
> schemes (optimise for features vs number of clients etc) and whatnot.
> 
> Any ideas how to implement that? Is there any prior work for anything
> like this? This is pretty hard limiting usability of upstream wireless
> drivers and I really want to find a proper solution.

I used a 'fwcfg' file that is loaded during ath10k initialization, from
same general location as the firmware.  Name is with pci-id or other unique
identifier like board files sometimes are named, and you get per radio
configuration at device load time.  I'm sure I posted a patch on this
some years ago, but I can point you to my current tree if you prefer.

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com