Re: patch "firmware loader: allow disabling of udev as firmware loader" added to driver-core tree

[Shuah Khan]

On Thu, Aug 7, 2014 at 1:57 AM, Takashi Iwai <tiwai@xxxxxxx> wrote:
>> >> Hm?  3.16 doesn't contain my patch yet.  It's merged for 3.17-rc1.
>> >
>> > Oh, you are right of course, I am on upstream kernel and I have your
>> > patch. I don't mean your match is causing the issue though ;-).
>> >
>>
>> I think this is what is going on and this patch is the cause:
>> fw_load_from_user_helper() is a stub that returns -ENOENT with this
>> patch.
>
> ... unless specifying the new Kconfig
> CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.  This is exactly the purpose
> of the commit.

Right - I figured that is the intent.

>
>> As a result, in _request_firmware() after fw_get_filesystem_firmware()
>> fails to find the file, fw_load_from_user_helper() gets called and it
>> returns right
>> away with -ENOENT.
>>
>> In some cases if rootfs mount is in progress, fw_load_from_user_helper()
>> steps into load the firmware.
>
> When a module in initrd requires a firmware, it should be put in
> initrd, too.

Right. This is something drivers have to watch out for with this change.

-- Shuah
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/