On Sat, Dec 27, 2014 at 6:15 PM, Rick Mann <[email protected]> wrote:
>
>> On Dec 27, 2014, at 15:23 , Robert Nelson <[email protected]> wrote:
>>
>> On Sat, Dec 27, 2014 at 4:52 PM, Chris Morgan <[email protected]> wrote:
>>> That's kind of disappointing to hear. Pio sounds like it means a lot of
>>> overhead if you are using a lot of usb bandwidth. I'm interested as we are
>>> using a bit of usb and a usb audio codec...
>>>
>>> Is this issue something exclusive to the ti kernel or also in mainline?
>>
>> It's just the last few outlier bugs for the DMA controller behind the
>> musb ip block..
>>
>> In v3.8.x we have PIO mode set by default too:
>>
>> CONFIG_USB_MUSB_DSPS=y
>> CONFIG_MUSB_PIO_ONLY=y
>>
>> https://github.com/beagleboard/linux/blob/1b8cd64cf49960d835591de1fee2282494858fa6/arch/arm/configs/bb.org_defconfig#L3345
>>
>> So it's not really a regression from a v3.8.x -> v3.14.x upgrade point.
>>
>> But if we start getting a fair number of user problems, i'm prepared
>> to push it back to pio mode quickly.
>
> Oh, this might be the issue I was experiencing with the later kernel. In my 
> other email I just posted ("Changes in 3.19 (was: How to make BBB pins work 
> after Ubuntu Trusty install?)"), I talked about the 3.18 kernel, but I 
> probably meant 3.14. That was weeks ago and I just don't remember how I got 
> to that situation (either upgrading the kernel or building my own).
>
> In any case, my USB audio dongle playback was terrible on a kernel >3.8.x, 
> works well on 3.8.

git clone https://github.com/beagleboard/linux
cd linux

git checkout origin/3.14.26-ti-r43 -b tmp
make ARCH=arm bb.org_defconfig

./scripts/config --disable CONFIG_USB_TI_CPPI41_DMA
./scripts/config --enable CONFIG_MUSB_PIO_ONLY

fakeroot make ARCH=arm  LOCALVERSION=-ti-r43-tmp
CROSS_COMPILE=/usr/bin/arm-linux-gnueabihf-  KDEB_PKGVERSION=1cross
KBUILD_DEBARCH=armhf deb-pkg

cp *.deb to bbb, then run:

sudo dpkg -i linux-image-*
sudo reboot

Regards,

-- 
Robert Nelson
http://www.rcn-ee.com/

-- 
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