linux-kernel - Re: [PATCH] iwlwifi: pcie: reduce "unsupported splx" to a warning

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Date:   Thu, 13 Oct 2016 12:01:09 +0300
From:   Luca Coelho <luca@...lho.fi>
To:     Chris Rorvick <chris@...vick.com>, Paul Bolle <pebolle@...cali.nl>
Cc:     Intel Linux Wireless <linuxwifi@...el.com>,
        Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
        Johannes Berg <johannes.berg@...el.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        Oren Givon <oren.givon@...el.com>,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iwlwifi: pcie: reduce "unsupported splx" to a warning

On Wed, 2016-10-12 at 12:50 -0500, Chris Rorvick wrote:
> Hi Luca,
> 
> FYI, It seems that Google does not like your email as I'm not
> receiving any of your messages in gmail.  Some responses below:

That's odd.  It works for me.  Replied privately to try to sort this
out.


> On Wed, 2016-10-12 at 15:24 +0300, Luca Coelho wrote:
> > Hi Chris,
> > On Tue, 2016-10-11 at 09:09 -0500, Chris Rorvick wrote:
> > > On Tue, Oct 11, 2016 at 5:11 AM, Paul Bolle <pebolle [at] tiscali> wrote:
> > > > > This is not coming from the NIC itself, but from the platform's ACPI
> > > > > tables. Can you tell us which platform you are using?
> > > 
> > > 
> > > Interesting. I'm running a Dell XPS 13 9350. I replaced the
> > > factory-provided Broadcom card with an AC 8260. I can update the
> > > commit log to reflect this.
> > 
> > 
> > Okay, so this makes sense. Those entries are probably formatted for
> > the Broadcom card, which the iwlwifi driver obviously doesn't
> > understand. The best we can do, as I already said, is to ignore values
> > we don't understand.
> 
> 
> This may already be apparent, but Dell sells two versions of the 9350:
> one with the Broadcom adapter and one with the AC 8260.  I just
> happened to find the former version at a deep discount at Costco so
> decided to chance it.  Turns out the Broadcom card is not so good even
> with new kernels so I upgraded.  Anyway, since Paul is seeing the same
> issue I don't think the values are intended to be Broadcom-specific.

Right, this is not for Broadcom.  I found out that this is something
Intel specifies as part of the entire platform's ACPI recommendations.


> On Wed, 2016-10-12 at 17:21 +0300, Luca Coelho wrote:
> > And, the values in the SPLX structs are being changed here, to DOM1,
> > LIM1, TIM1 etc., before being returned. Â This also matches your
> > description that, at runtime, you got something different than the pure
> > dump. Â If you follow these DOM*, LIM*, TIM* symbols, you'll probably
> > end up getting the values you observed at runtime.
> 
> 
> Probably not important, but it seems that there is some additional
> indirection.  The only values I'm seeing associated with those symbols
> are 8 and 16:
> 
>     $ grep -e 'DOM[0-9]' -e 'LIM[0-9]' -e 'TIM[0-9]' dsdt.dsl | grep -v Store
>     DOM1,   8,
>     LIM1,   16,
>     TIM1,   16,
>     DOM2,   8,
>     LIM2,   16,
>     TIM2,   16,
>     DOM3,   8,
>     LIM3,   16,
>     TIM3,   16,

Yeah, there are often many levels of indirection.  These settings can
be also tied to the configuration that is reachable by the user in the
BIOS setup, so you never know.

The easiest way is probably to run the ASL with acpiexec and execute
the method...

> > I'll send you a patch for testing soon.
> 
> 
> I will keep an eye on the list archive, thanks!

I'll ping you from my Intel address and provide you with a link to the
patch, to make it easier for you. ;)

--
Cheers,
Luca.