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Date:   Thu, 4 Aug 2022 11:35:26 +0100
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Subject: soundwire qcom slimbus dependency (was Re: [PATCH 0/2] arm64
 defconfig: Get faddr2line working)
To:     Arnd Bergmann <arnd@arndb.de>, Jonathan Marek <jonathan@marek.ca>
CC:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Olof Johansson <olof@lixom.net>, "SoC Team" <soc@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Vinod Koul <vkoul@kernel.org>
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From:   John Garry <john.garry@huawei.com>
In-Reply-To: <CAK8P3a2HGYJZvcXM+9fROys5A6c40zFWD2qATT4xssSJf6hRfQ@mail.gmail.com>
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On 28/07/2022 13:03, Arnd Bergmann wrote:
> On Thu, Jul 28, 2022 at 1:57 PM Jonathan Marek <jonathan@marek.ca> wrote:
>> On 7/28/22 5:09 AM, Arnd Bergmann wrote:
>>> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
>>> index 22b706350ead..f65c7737c2db 100644
>>> --- a/drivers/soundwire/qcom.c
>>> +++ b/drivers/soundwire/qcom.c
>>> @@ -1289,11 +1289,7 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>>>           data = of_device_get_match_data(dev);
>>>           ctrl->rows_index = sdw_find_row_index(data->default_rows);
>>>           ctrl->cols_index = sdw_find_col_index(data->default_cols);
>>> -#if IS_REACHABLE(CONFIG_SLIMBUS)
>>> -       if (dev->parent->bus == &slimbus_bus) {
>>> -#else
>>> -       if (false) {
>>> -#endif
>>> +       if (IS_ENABLED(CONFIG_SLIMBUS) && dev->parent->bus == &slimbus_bus) {
>>>                   ctrl->reg_read = qcom_swrm_ahb_reg_read;
>>>                   ctrl->reg_write = qcom_swrm_ahb_reg_write;
>>>                   ctrl->regmap = dev_get_regmap(dev->parent, NULL);
>>>
>>
>> This relies on the compiler optimizing out the reference to slimbus_bus,
>> which doesn't exist in the CONFIG_SLIMBUS=n case (not tested, but I
>> think this means an O0 build will fail?).
> 
> That is correct: We rely on this everywhere in the kernel, which is why
> it is impossible to build kernels with -O0.
> 

Was there any patch sent to fix/improve this? I could not see any. Or 
any plan to do so?

Thanks,
John