Re: [PATCH 1/1] hdsp: allow firmware loading from inside the kernel

["Raphaël Doursenaud" <rdoursenaud@free.fr>]

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Takashi Iwai a écrit :
> At Tue, 12 May 2009 10:01:20 +0200,
> Raphaël Doursenaud wrote:
>> Takashi Iwai a écrit :
>>> At Tue, 12 May 2009 09:41:36 +0200,
>>> Raphaël Doursenaud wrote:
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>>>> Takashi Iwai a écrit :
>>>>> At Tue, 12 May 2009 09:25:27 +0200,
>>>>> Raphaël Doursenaud wrote:
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>>>>>> Takashi Iwai a écrit :
>>>>>>> At Tue, 12 May 2009 09:05:19 +0200,
>>>>>>> Raphaël Doursenaud wrote:
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>>>>>>>> Takashi Iwai a écrit :
>>>>>>>>> At Tue, 12 May 2009 08:47:29 +0200,
>>>>>>>>> Raphaël Doursenaud wrote:
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>>>>>>>>>> Takashi Iwai a écrit :
>>>>>>>>>>> At Tue, 12 May 2009 08:16:08 +0200,
>>>>>>>>>>> Raphaël Doursenaud wrote:
>>>>>>>>>>>> From: Raphaël Doursenaud <rdoursenaud@free.fr>
>>>>>>>>>>>>
>>>>>>>>>>>> Allow the use of  the FIRMWARE_IN_KERNEL option with hdsp cards and
>>>>>>>>>>>> in-kernel driver.
>>>>>>>>>>> Did it really work without problems?
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Takashi
>>>>>>>>>> Tested over the weekend with two multifaces in my DAW.
>>>>>>>>>> Got no problem.
>>>>>>>>> Interesting.
>>>>>>>>> Did you build the firmware file into the kernel, or not?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Takashi
>>>>>>>> Yes I built all hdsp fimware files (multiface_firmware.bin
>>>>>>>> multiface_firmware_rev11.bin digiface_firmware.bin
>>>>>>>> digiface_firmware_rev11.bin) into the kernel.
>>>>>>>> It's the aim of this patch.
>>>>>>> Well, the problem I'm concerned is that the driver can be compiled
>>>>>>> in even if you have no built-in firmware.  And there is no restriction
>>>>>>> or dependency check in Kconfig, so far.
>>>>>>>
>>>>>>> Could you test how the kernel behaves without the built-in firmware?
>>>>>>> Does it hang or give any critical error?
>>>>>>>
>>>>>>>
>>>>>>> thanks,
>>>>>>>
>>>>>>> Takashi
>>>>>> Could you be more specific?
>>>>>> I'm not sure to understand why it could be a problem.
>>>>>> Do you think that if I set FIRMWARE_IN_KERNEL without compiling the
>>>>>> firmware(s) in-kernel the request_firmware() will not resolve and cause
>>>>>> an error?
>>>>> Yes, exactly.
>>>>> request_firmware() shall fail in that case likely after a long
>>>>> time-out (unless you have the firmware files in initrd) because there
>>>>> is really no file / data available at the time it's called.
>>>>> And I'm not sure whether this could lead to a fatal operation error.
>>>>>
>>>>>
>>>>> Takashi
>>>> AFAIK this is handled in the code (from line 5080) and should lead to
>>>> "Hammerfall-DSP: couldn't get firmware from userspace. try using hdsploader"
>>> Yep, a fallback mechanism is found in hdsp driver itself.
>>> But the driver probe hangs for too long time, and I'm just worried
>>> about its influence on the whole kernel boot-up.
>>>
>>>> I'm building a kernel to test that case.
>>> Thanks.
>>>
>>>
>>> Takashi
>> Wow, you're right! Didn't think about that...
>>
>> It hangs for about 45s on :
>> Hammerfall-DSP: wait for FIFO status <= 0 failed after 30 iterations
>> RME Hammerfall DSP 0000:05:02.0: firmware: requesting
>> multiface_firmware_rev11.bin
>>
>> before going on with :
>> Hammerfall-DSP: cannot load firmware multiface_firmware_rev11.bin
>> Hammerfall-DSP: couldn't get firmware from userspace. try using hdsploader
>> Hammerfall-DSP: card initialization pending : waiting for firmware
> 
> OK, so it doesn't lead to any critical error?
> Then it's better than the worst case I thought of :)
> 
>> I wonder what would be the best way to deal with that while still
>> enabling in-kernel firmware.
> 
> Well, it's basically a problem of the request_firmware() itself, so
> we can't fix the behavior properly in the driver side.  There is an
> option to use *_nowait() call, but this will end up with a mess of
> code flow, I'm afraid.
> 
> So, I'm going to apply your patch.  But, maybe we should add a warning
> in Kconfig comment, such as
> 
> comment "Don't forget to add built-in firmwares for HDSP driver"
> 	depends on SND_HDSP=y
> 
> or so...  Suggestions of a better text are appreciated.
> 
> 
> thanks,
> 
> Takashi

mmm sounds good to me.
With the patch I'm about to propose to correct the firmwares path it
should fit most situations.

Thanks a lot for your input!

- --
Raphaël Doursenaud
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