Re: [PATCH] ARM: exynos_defconfig: Enable WiFi-Ex as a module instead built-in
From: Javier Martinez Canillas
Date: Wed Sep 30 2015 - 03:54:26 EST
On 09/30/2015 09:37 AM, Krzysztof Kozlowski wrote:
> On 30.09.2015 16:22, Javier Martinez Canillas wrote:
>> Hello Krzysztof,
>> On 09/30/2015 02:36 AM, Krzysztof Kozlowski wrote:
>>> On 29.09.2015 21:42, Javier Martinez Canillas wrote:
>>>> The Marvell WiFi-Ex driver tries to load a firmware on probe. So if the
>>>> driver is built-in and probed before a firmware is available, this is
>>>> not loaded and the chip does not work.
>>>> This happens for example if an initramfs isn't used since the driver is
>>>> probed before the root filesystem is mounted.
>>>> Change the default config since the driver isn't needed for machines to
>>>> boot and is more convenient to have it enabled as a module to avoid
>>>> requiring an initramfs or to have the firmware built into the kernel.
>>>> Signed-off-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
>>>> arch/arm/configs/exynos_defconfig | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>> The user-space can always initiate re-probing of device - just re-bind
>> It is true that you can force a re-probing from user-space by doing:
>> $ echo "mmc2:0001:1" > /sys/bus/sdio/drivers/mwifiex_sdio/unbind
>> $ echo "mmc2:0001:1" > /sys/bus/sdio/drivers/mwifiex_sdio/bind
> I suppose the unbind won't be needed, because device aborted the
> probe... so only one another bind.
Right, only the bind is needed indeed since the device is unbind
after the firmware loading fails. I just wanted to confirm that
I understood what you said before correctly.
>> a) This is not obvious. In fact, I didn't think that possibility
>> before you mentioned and I've been using Linux for many years :)
> Eh, questionable. Obvious for me :)
Fair enough, maybe is just me then :)
>> b) This is not something that isn't done automatically by init systems.
err, I wanted to say "is not something that is done automatically" but
fortunately you understood what I meant.
>> So what users will see is that the driver was probed successfully but
>> the firmware fails to load later (since the driver users the async
>> request_firmware_nowait function to request the firmware).
>>> it. However I assume that driver cannot work without firmware?
>> Yes, it doesn't. I explained this in the commit message. Do you
>> think it should be made more clear?
> No, its OK, I agree.
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
Great, thanks a lot for your feedback and review!
> Best regards,
Javier Martinez Canillas
Open Source Group
Samsung Research America
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