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Message-ID: <eb11e6b1-01cb-78af-2b2d-5884106ad9c7@infradead.org>
Date:   Tue, 31 May 2022 09:32:22 -0700
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Subject: Re: [PATCH v16 4/4] m68k: introduce a virtual m68k machine
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To:     Laurent Vivier <laurent@vivier.eu>, linux-kernel@vger.kernel.org
Cc:     Alexandre Belloni <alexandre.belloni@bootlin.com>,
        linux-m68k@lists.linux-m68k.org,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        linux-rtc@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        John Stultz <john.stultz@linaro.org>,
        Stephen Boyd <sboyd@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Alessandro Zummo <a.zummo@towertech.it>
References: <20220406201523.243733-1-laurent@vivier.eu>
 <20220406201523.243733-5-laurent@vivier.eu>
 <3b783435-e734-5391-e758-d709e0462839@infradead.org>
 <64ce78bf-b81b-1eec-74f3-650a72f2874b@vivier.eu>
From:   Randy Dunlap <rdunlap@infradead.org>
In-Reply-To: <64ce78bf-b81b-1eec-74f3-650a72f2874b@vivier.eu>
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Precedence: bulk


On 5/30/22 23:05, Laurent Vivier wrote:
> Le 31/05/2022 à 03:14, Randy Dunlap a écrit :
>> Hi--
> 
> Hi,
> 
>> On 4/6/22 13:15, Laurent Vivier wrote:
>>> diff --git a/arch/m68k/Kconfig.machine b/arch/m68k/Kconfig.machine
>>> index eeab4f3e6c19..188a8f8a0104 100644
>>> --- a/arch/m68k/Kconfig.machine
>>> +++ b/arch/m68k/Kconfig.machine
>>> @@ -149,6 +149,23 @@ config SUN3
>>>           If you don't want to compile a kernel exclusively for a Sun 3, say N.
>>>   +config VIRT
>>> +    bool "Virtual M68k Machine support"
>>> +    depends on MMU
>>> +    select GENERIC_CLOCKEVENTS
>>> +    select GOLDFISH
>>> +    select GOLDFISH_TIMER
>>> +    select GOLDFISH_TTY
>>> +    select M68040
>>> +    select MMU_MOTOROLA if MMU
>>> +    select RTC_CLASS
>>> +    select RTC_DRV_GOLDFISH
>>> +    select TTY
>>> +    select VIRTIO_MMIO
>>
>> This select VIRTIO_MMIO can cause a kconfig warning:
>>
>> WARNING: unmet direct dependencies detected for VIRTIO_MMIO
>>    Depends on [n]: VIRTIO_MENU [=n] && HAS_IOMEM [=y] && HAS_DMA [=y]
> 
> In my repo, VIRTIO_MMIO has no dependency on VIRTIO_MENU:
> 
> ./drivers/virtio/Kconfig
> config VIRTIO_MMIO
>         tristate "Platform bus driver for memory mapped virtio devices"
>         depends on HAS_IOMEM && HAS_DMA

As Arnd explained...

> 
>>    Selected by [y]:
>>    - VIRT [=y] && M68KCLASSIC [=y] && MMU [=y]
> 
> How do you generate this warning?

It's just a random randconfig.

> The first version of my patch added the VIRTIO_MENU but Geert said it's not necessary because VIRTIO_MENU defaults to y.
> 
> https://lore.kernel.org/lkml/CAMuHMdUFh2W-bY5Ez1aOTZQjq0=THvmOf22JdxWoNNtFLskSzw@mail.gmail.com/

It's still a user-settable value and can be disabled, so the Kconfig entry
should account for (allow for) that, either with 'select' or 'depends on'.

>>
>>> +    help
>>> +      This options enable a pure virtual machine based on m68k,
>>> +      VIRTIO MMIO devices and GOLDFISH interfaces (TTY, RTC, PIC)
>>
>> The sentence above needs an ending period ('.').
>>
> 
> I agree.
> 
> Thanks,
> Laurent
> 

-- 
~Randy