High CPU load produced by USB (DW2)

Marek Vasut marek.vasut at gmail.com
Wed Mar 7 14:42:58 PST 2018

On 03/06/2018 09:09 AM, Minas Harutyunyan wrote:
> Hi,
> On 3/6/2018 10:45 AM, Minas Harutyunyan wrote:
>> Hi,
>> On 3/5/2018 11:14 PM, Marek Vasut wrote:
>>> On 02/20/2018 06:51 AM, Minas Harutyunyan wrote:
>>> [...]
>>>>>>> Is there a way to reduce that or is that the absolute minimum in HS mode?
>>>>>> We already discussed, in this email thread earlier, why SOF interrupts
>>>>>> required and unmasked.
>>>>>> Only in case when connected device with CTRL+BLK EP's only (like flash
>>>>>> drive) and directly connected to cores root HUB, SOF's will be masked.
>>>>> That's the setup I have on Altera SoCFPGA, yet the SOFs are still present.
>>>> Could you please send verbose lsusb on connected to dwc2 device
>>> See attached
>>>> and driver debug log.
>>> What exactly do you mean by this one ?
>> Enable debugging messages and verbose debugging messages for dwc2 from
>> make menuconfig. Provide dmesg starting from dwc2 load till HS device
>> connected to dwc2 port and enumerated.
>> Thanks,
>> Minas
> Driver debug log not required.
> Based on lsusb output: to dwc2 port connected "Standard Microsystems
> Corp. USB 2.0 Hub" to which connected your HS device "SanDisk Corp.
> Ultra". Because of connected HUB, which have periodic endpoint
> (Interrupt IN EP1) like all HUB's, dwc2 forced in Buffer DMA mode unmask
> SOF interrupts.

I don't understand the last part, can you rephrase ?

What does that mean regarding the SOF question above ?

More information about the Linux-rockchip mailing list