[LAU] Google TV device w/ AV out

Jeremy Jongepier jeremy at autostatic.com
Sat Jun 29 12:23:42 UTC 2013


On 06/29/2013 02:58 AM, Patrick Shirkey wrote:
>
> On Fri, June 28, 2013 11:52 pm, Jeremy Jongepier wrote:
>> On 06/19/2013 03:39 PM, Jeremy Jongepier wrote:
>>> On 06/19/2013 12:08 AM, Dan MacDonald wrote:
>>>> That's what I expected, seeing how little success I've had on my
>>>> Pandaboard
>>>> with J2 git. Have you tried J1 too?
>>>
>>> Ok, got Jack1 running. Recompiled the kernel without debugging and
>>> disabled WiFi. I now see I can also tweak the IRQ threads, nice.
>>>
>>> Jeremy
>>
>> Just an update. Getting things stable is quite some work actually but
>> I'm slowly getting there. I've stripped the kernel config a bit further
>> and have a good starting point now. Some findings:
>> * RT patch doesn't apply cleanly. I've hacked my way through it but
>> can't get it to compile.
>
> What are the error messages?
>

An undefined reference to printascii in some RockChip related driver:

drivers/built-in.o: In function `dbg':
mtk_wcn_cmb_stub_rockchip.c:(.text+0x3a598): undefined reference to 
`printascii'
make: *** [.tmp_vmlinux1] Error 1

>
>> * I've tried using threadirqs but then the stick wouldn't boot (couldn't
>> find any rootfs to load from MMC). Applied this patch:
>> http://www.spinics.net/lists/linux-rt-users/msg08062.html
>> Then I get threaded IRQs but it's not much of an improvement, the USB
>> IRQ that has the WiFi connected to it consumes a lot of CPU and I can't
>> get JACK to run stable. I did try prioritizing IRQs with rtirq but it
>> didn't make any difference, the board seems to run better without
>> threaded IRQs.
>> * Tried dwc_otg.speed=1 as a kernel parameter, no improvement.
>> * This thing doesn't have serial console access, I've tried all possible
>> pads, vias and pins but no joy :( I did manage to solder a button on the
>> board that allows me to directly boot into flash mode which is already
>> quite convenient.
>> * No ethernet access, only WiFi. But enabling WiFi means JACK won't run
>> properly. Also tried an external USB dongle, same problems basically.
>
> What is the wifi chipset?
>

Of the rk3066 based device? Realtek 8188eu. The dongle is using a Ralink 
rt53xx chipset.

>
>> * So I have to work using the HDMI connection and a keyboard. Had to
>> disable blanking otherwise JACK would crash.
>>
>> Well, that last example sums it all up I guess, this board isn't really
>> made for doing real-time audio. Unless people prove me wrong, I'd love
>> to hear what other people's experiences are. Any tips, ideas,
>> suggestions? I'm now glazing at amsynth 1.4.0 running headless while
>> JACK occasionally spits out 'delay of .... usecs exceeds estimated spare
>> time of .....; restart ...' messages and that with jackd -P84 -p32
>> -t2000 -dalsa -n3 -p128 -s
>
> What happens at higher period values and if you disable duplex mode?
>

I could test that but haven't done so yet because my goal is to have 
JACK running with -p64 and full duplex. JACK runs stable at -p128 but 
then the audio output is distorted and can't fix it with resetting the 
JACK buffersize (this 'trick' works with the RPi though). So far I'm 
getting the idea that at least the RK3066 based board I have is unusable 
for my purpose. And I have a feeling it won't be much better with a 
RK3188 based board.

Regards,

Jeremy

>
>
>> I HAVE to use the ALSA -s (softmode) option otherwise the whole USB
>> stack locks up. Pffff, maybe I should buy a board that does work, like
>> the pcDuino or BeagleBone Black.
>>
>> Regards,
>>
>> Jeremy
>> _______________________________________________
>> Linux-audio-user mailing list
>> Linux-audio-user at lists.linuxaudio.org
>> http://lists.linuxaudio.org/listinfo/linux-audio-user
>>
>
>
> --
> Patrick Shirkey
> Boost Hardware Ltd
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