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From:   Christian Lamparter <chunkeey@gmail.com>
To:     Kalle Valo <kvalo@codeaurora.org>
Cc:     linux-wireless@vger.kernel.org
Subject: Re: [PATCH] carl9170: fix enum compare splat
Date:   Thu, 20 Jun 2019 16:41:00 +0200
Message-ID: <4392478.8kWN0Ehzps@debian64>
In-Reply-To: <87a7ef9jp2.fsf@kamboji.qca.qualcomm.com>
References: <20190608144947.744-1-chunkeey@gmail.com> <1601416.I41mb68Wgz@debian64> <87a7ef9jp2.fsf@kamboji.qca.qualcomm.com>
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On Tuesday, June 18, 2019 2:11:53 PM CEST Kalle Valo wrote:
> Christian Lamparter <chunkeey@gmail.com> writes:
> > On Monday, June 10, 2019 9:06:30 AM CEST Kalle Valo wrote:
> >> Christian Lamparter <chunkeey@gmail.com> writes:
> >>=20
> >> > This patch fixes a noisy warning triggered by -Wenum-compare
> >> >
> >> > |main.c:1390:31: warning: comparison between =E2=80=98enum nl80211_a=
c=E2=80=99
> >> > |	and =E2=80=98enum ar9170_txq=E2=80=99 [-Wenum-compare]
> >> > |  BUILD_BUG_ON(NL80211_NUM_ACS > __AR9170_NUM_TXQ);
> >> > |                               ^
> >> > | [...]
> >> >
> >> > This is a little bit unfortunate, since the number of queues
> >> > (hence NL80211_NUM_ACS) is a constant based on the IEEE 802.11
> >> > (much like IEEE80211_NUM_ACS) and __AR9170_NUM_TXQ is more or
> >> > less defined by the AR9170 hardware.
> >>=20
> >> Is the warning enabled by default? TBH I'm not seeing how useful this
> >> warning is for kernel development.
> >
> > It is included in the "-Wall" (which is coming from "KBUILD_CFLAGS"=20
> > in the main Makefile).
> >
> > I tried debian's gcc starting from 4.6 to the lastest 8.3. They all
> > complain about it in various degrees.
> >
> > https://gcc.gnu.org/onlinedocs/gcc-4.6.0/gcc/Warning-Options.html#Warni=
ng-Options
>=20
> Ok, odd that I haven't noticed this warning. Maybe I have been just
> blind.

Sorry. No, I messed up there. I made a patch back in the day during the spe=
ctre
mac80211 patches that I kept in my tree for the driver. But I now remember =
that
I never published those because of that exact "warning".
These lines are coming from there.
=20
> >> > --- a/drivers/net/wireless/ath/carl9170/main.c
> >> > +++ b/drivers/net/wireless/ath/carl9170/main.c
> >> > @@ -1387,7 +1387,7 @@ static int carl9170_op_conf_tx(struct ieee8021=
1_hw *hw,
> >> >  	int ret;
> >> > =20
> >> >  	BUILD_BUG_ON(ARRAY_SIZE(ar9170_qmap) !=3D __AR9170_NUM_TXQ);
> >> > -	BUILD_BUG_ON(NL80211_NUM_ACS > __AR9170_NUM_TXQ);
> >> > +	BUILD_BUG_ON((size_t)NL80211_NUM_ACS > (size_t)__AR9170_NUM_TXQ);
> >>=20
> >> IMHO this just makes the code worse. Does it make sense to workaround
> >> (stupid) compiler warnings like this?
> >
> > True. What's worse: This isn't really code. The BUILD_BUG_ON Macro is t=
here
> > to guard but it's getting compiled away. I could also just drop it.
>=20
> Either way is fine for me. If the GCC (by default) emits a warning for
> this we need to silence that warning, so in that respect I guess we
> should apply this. Unless better solutions come up, of course :)
Note: I dropped this patch from patchwork. So, there's nothing that
needs to be done now ;)

Well, except OT: Would you mind adding the QCA4019 boardfiles that
have accumulated over the past six-ish months?

<https://www.mail-archive.com/ath10k@lists.infradead.org/msg09966.html>

That list already had:
ath10k-firmware: QCA4019 hw1.0: Add ASUS Lyra specific BDFs
ath10k-firmware: QCA4019 hw1.0: Add Linksys EA6350v3
ath10k-firmware: QCA4019 hw1.0: Add Qxwlan E2600AC specific BDFs
ath10k-firmware: QCA4019 hw1.0: Update OpenMesh A62 specific BDFs
ath10k-firmware: QCA9888 hw2.0: Update OpenMesh A62 specific BDFs
ath10k-firmware: QCA4019 hw1.0: Update OpenMesh A42 specific BDFs
ath10k-firmware: QCA4019 hw1.0: Add ALFA Network AP120C-AC specific BDF
ath10k-firmware: QCA4019 hw1.0: Add AVM FRITZ!Box 7530 specific BDFs
ath10k-firmware: QCA4019 hw1.0: Update Linksys EA6350v3 specific BDFs

and now there's even more:

+ ath10k-firmware: QCA4019 hw1.0: Add Qxwlan E2600AC specific BDFs
 (Watch out, there are multiple versions! The first ones are dodgy
 with a bad crc)=20
 This should be the right "one"
 <https://www.mail-archive.com/ath10k@lists.infradead.org/msg10007.html>

+ ath10k-firmware: QCA4019 hw1.0: Add AVM FRITZ!Repeater 3000 specific BDFs
 <https://www.mail-archive.com/ath10k@lists.infradead.org/msg10101.html>

+ ath10k-firmware: IPQ4018 hw1.0: Add EnGenius ENS620EXT specific BDFs
<http://lists.infradead.org/pipermail/ath10k/2019-March/013034.html>

+ ath10k-firmware: QCA9984 hw1.0: Update Netgear Orbi Pro SRK60 specific BD=
=46s
  ath10k-firmware: QCA4019 hw1.0: Update Netgear Orbi Pro SRK60 specific BD=
=46s

  One for QCA9984 and one for two QCA4019
<https://www.mail-archive.com/ath10k@lists.infradead.org/msg10170.html>
<https://www.mail-archive.com/ath10k@lists.infradead.org/msg10171.html>

+ ath10k-firmware: IPQ4019 hw1.0: Add BDF for Linksys EA8300 [1/2]
  ath10k-firmware: QCA9888 hw1.0: Add BDF for Linksys EA8300 [2/2]

<http://lists.infradead.org/pipermail/ath10k/2019-May/013403.html>
<http://lists.infradead.org/pipermail/ath10k/2019-May/013404.html>

Cheers,
Christian