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In-Reply-To: <e5edd92e-ab47-4a55-9276-5a7d160fd399@quicinc.com>
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Wed, 15 May 2024 13:10:54 +0900
Message-ID: <CAK7LNAQ11Pt85_T9kvYYbqfnjMSH_Yjwvz52E+Tcmw8jS-wvDw@mail.gmail.com>
Subject: Re: [PATCH] wifi: ath10k: fix QCOM_RPROC_COMMON dependency
To: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>, Kalle Valo <kvalo@kernel.org>, 
	Jeff Johnson <jjohnson@kernel.org>, Stephen Boyd <swboyd@chromium.org>, 
	Rakesh Pillai <quic_pillair@quicinc.com>, linux-wireless@vger.kernel.org, 
	ath10k@lists.infradead.org, linux-kernel@vger.kernel.org, 
	stable@vger.kernel.org, linux-kbuild@vger.kernel.org
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On Wed, May 15, 2024 at 3:14=E2=80=AFAM Jeff Johnson <quic_jjohnson@quicinc=
.com> wrote:
>
> On 5/14/2024 10:45 AM, Masahiro Yamada wrote:
> > On Tue, May 14, 2024 at 11:43=E2=80=AFPM Jeff Johnson <quic_jjohnson@qu=
icinc.com> wrote:
> >>
> >> On 5/11/2024 3:49 AM, Dmitry Baryshkov wrote:
> >>> If ath10k_snoc is built-in, while Qualcomm remoteprocs are built as
> >>> modules, compilation fails with:
> >>>
> >>> /usr/bin/aarch64-linux-gnu-ld: drivers/net/wireless/ath/ath10k/snoc.o=
: in function `ath10k_modem_init':
> >>> drivers/net/wireless/ath/ath10k/snoc.c:1534: undefined reference to `=
qcom_register_ssr_notifier'
> >>> /usr/bin/aarch64-linux-gnu-ld: drivers/net/wireless/ath/ath10k/snoc.o=
: in function `ath10k_modem_deinit':
> >>> drivers/net/wireless/ath/ath10k/snoc.c:1551: undefined reference to `=
qcom_unregister_ssr_notifier'
> >>>
> >>> Add corresponding dependency to ATH10K_SNOC Kconfig entry so that it'=
s
> >>> built as module if QCOM_RPROC_COMMON is built as module too.
> >>>
> >>> Fixes: 747ff7d3d742 ("ath10k: Don't always treat modem stop events as=
 crashes")
> >>> Cc: stable@vger.kernel.org
> >>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> >>> ---
> >>>  drivers/net/wireless/ath/ath10k/Kconfig | 1 +
> >>>  1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/drivers/net/wireless/ath/ath10k/Kconfig b/drivers/net/wi=
reless/ath/ath10k/Kconfig
> >>> index e6ea884cafc1..4f385f4a8cef 100644
> >>> --- a/drivers/net/wireless/ath/ath10k/Kconfig
> >>> +++ b/drivers/net/wireless/ath/ath10k/Kconfig
> >>> @@ -45,6 +45,7 @@ config ATH10K_SNOC
> >>>       depends on ATH10K
> >>>       depends on ARCH_QCOM || COMPILE_TEST
> >>>       depends on QCOM_SMEM
> >>> +     depends on QCOM_RPROC_COMMON || QCOM_RPROC_COMMON=3Dn
> >>>       select QCOM_SCM
> >>>       select QCOM_QMI_HELPERS
> >>>       help
> >>>
> >>> ---
> >>> base-commit: 75fa778d74b786a1608d55d655d42b480a6fa8bd
> >>> change-id: 20240511-ath10k-snoc-dep-862a9da2e6bb
> >>
> >> I see how this fixes the problem, but this doesn't seem like an ideal
> >> solution. The fact that the *_ssr_notifier() functions are correctly p=
rotected
> >> by conditional compilation ideally should mean that clients don't need=
 to call
> >> call out this as a dependency. Otherwise, it would mean we'd need to d=
o this
> >> for all feature flags.
> >
> >
> > It depends on if qcom_common.c is optional for ath10k_snoc.
> >
> > If it is optional, this patch is correct.
>
> At least from a build perspective it is optional


You need to make a decision from a run-time perspective
(that is, whether you are fine with having
ar_snoc->notifier =3D=3D NULL)


If you are able to build the kernel successfully
but you get a run-time error (e.g. NULL pointer dereference),
it is even worse because run-time debugging is generally more
difficult than compile-time debugging.


--=20
Best Regards
Masahiro Yamada