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Message-ID: <01c8dc05-76d1-478e-a4e4-3eab8d6aeaf9@quicinc.com>
Date: Wed, 15 May 2024 15:43:42 -0700
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Subject: Re: [PATCH] wifi: ath10k: fix QCOM_RPROC_COMMON dependency
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To: Masahiro Yamada <masahiroy@kernel.org>
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>
References: <20240511-ath10k-snoc-dep-v1-1-9666e3af5c27@linaro.org>
 <12a208d7-f36b-4953-abff-323a15452b3c@quicinc.com>
 <CAK7LNASyBNbxm-e+iZ=7pOJg-a-Zm84O6RNcqiUjZQH7f9r3Lw@mail.gmail.com>
 <e5edd92e-ab47-4a55-9276-5a7d160fd399@quicinc.com>
 <CAK7LNAQ11Pt85_T9kvYYbqfnjMSH_Yjwvz52E+Tcmw8jS-wvDw@mail.gmail.com>
From: Jeff Johnson <quic_jjohnson@quicinc.com>
In-Reply-To: <CAK7LNAQ11Pt85_T9kvYYbqfnjMSH_Yjwvz52E+Tcmw8jS-wvDw@mail.gmail.com>
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On 5/14/2024 9:10 PM, Masahiro Yamada wrote:
> On Wed, May 15, 2024 at 3:14 AM 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 PM Jeff Johnson <quic_jjohnson@quicinc.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/wireless/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=n
>>>>>       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 protected
>>>> 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 do 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 == 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.

The current patch maintains the existing logic, so that is my preference.