Re: High CPU load produced by USB (DW2)

[Mirza Krak <mirza.krak-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 8 February 2018 at 14:53, Minas Harutyunyan
<Minas.Harutyunyan@synopsys.com> wrote:
> On 2/8/2018 5:07 PM, Mirza Krak wrote:
>> On 8 February 2018 at 12:02, Minas Harutyunyan
>> <Minas.Harutyunyan@synopsys.com> wrote:
>>> Hi Mirza,
>>>
>>> On 2/7/2018 1:49 PM, Mirza Krak wrote:
>>
>> < snip >
>>
>>>
>>> Could you please provide additional info:
>>> 1. Does your core support descriptor DMA mode? (bits 31 and 30 of GHWCFG4).
>>> 2. Version of core (GSNPSID)?
>>
>> It does seem to support descriptor DMA mode, and content of both
>> GHWCFG4 and GSNPSID are posted below.
>>
>> root@esp5-d1:~# dmesg | grep -E "GHWCFG4|GSNPSID"
>> [    1.109298] dwc2 ff540000.usb: GSNPSID @0xF0940040 : 0x4F54310A
>> [    1.109344] dwc2 ff540000.usb: GHWCFG4 @0xF0940050 : 0xC8004030
>> [    1.489016] dwc2 ff580000.usb: GSNPSID @0xF09C0040 : 0x4F54310A
>> [    1.489063] dwc2 ff580000.usb: GHWCFG4 @0xF09C0050 : 0xDBF04030
>>
>> Full register dump at boot (no devices connected) can be found at [1].
>>
>>> 3. Do you connect any HS HUB between dwc core port and keyboard? Is it
>>> available connection scenarios when Split traffic generated?
>>
>> There is actually an HS HUB (FE1_QFP48) between dwc core and keyboard,
>> I was not aware of it but it is mounted on the board.
>>
>>
>> [1]. https://urldefense.proofpoint.com/v2/url?u=https-3A__gist.github.com_mirzak_a6245dddd4670f3b908a9783f9db8b0d&d=DwIFaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=6z9Al9FrHR_ZqbbtSAsD16pvOL2S3XHxQnSzq8kusyI&m=FuRmhDEOJlbUvuyApaxG_YmB514C3IOGSzs6Mq_fzC0&s=ELF0UP4IluOiL35JlnFjiltWZx-BcTIsTaPjaWb0RFk&e=
>>
> Actually your core supported DDMA mode, moreover core allow SW to
> dynamically switch between BDMA and DDMA after core reset.
> If dwc2 core work in DDMA mode then core can track (u)frames internally
> and unmasking SOF's not required, but Host in DDMA doesn't support Split
> transfers. This is why, in your case (FS/LS keyboard connected to HS
> HUB), core switched to BDMA and unmasking SOF interrupt to track (u)frames.

Thank you for your valuable respons.

It is indeed as you mentioned the combination of HS and FS/LS devices
that trigger the high CPU load. Running HS only devices does not
produce any noticeable load.

But I am confused by one thing, I have two different boards with the
same SoC and same version of the DWC2 IP. Both boards have an internal
USB hub for the external connectors, though it seems that they have
different types of HUB' s. And I only have problems with one of them.
The second board does not have a problem mixing HS and FS/LS devices.
Is it possible that the USB HUB has some kind of "offloading" for the
Split transfers?

Tinkerboard USB hub (works well when mixing HS and FS/LS devices)
----------------------------

$ lsusb -t
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=ehci-platform/1p, 480M
    |__ Port 1: Dev 2, If 0, Class=Audio, Driver=, 480M
    |__ Port 1: Dev 2, If 1, Class=Audio, Driver=, 480M
    |__ Port 1: Dev 2, If 2, Class=Audio, Driver=, 480M
    |__ Port 1: Dev 2, If 3, Class=Audio, Driver=, 480M
    |__ Port 1: Dev 2, If 4, Class=Audio, Driver=, 480M
    |__ Port 1: Dev 2, If 5, Class=Audio, Driver=, 480M
    |__ Port 1: Dev 2, If 255, Class=Human Interface Device, Driver=usbhid, 480M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=dwc2/1p, 480M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc2/1p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M
        |__ Port 3: Dev 4, If 0, Class=Audio, Driver=, 12M
        |__ Port 3: Dev 4, If 1, Class=Audio, Driver=, 12M
        |__ Port 4: Dev 3, If 0, Class=Human Interface Device,
Driver=usbhid, 12M

$ lsusb -d 05e3:0610 -v

Bus 001 Device 002: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         2 TT per port
  bMaxPacketSize0        64
  idVendor           0x05e3 Genesys Logic, Inc.
  idProduct          0x0610 4-port hub
  bcdDevice           32.98
  iManufacturer           0
  iProduct                1 USB2.0 Hub
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           41
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      1 Single TT
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0001  1x 1 bytes
        bInterval              12
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      2 TT per port
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0001  1x 1 bytes
        bInterval              12
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             4
  wHubCharacteristic 0x00e0
    Ganged power switching
    Ganged overcurrent protection
    TT think time 32 FS bits
    Port indicators
  bPwrOn2PwrGood       50 * 2 milli seconds
  bHubContrCurrent    100 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0xff
 Hub Port Status:
   Port 1: 0000.0100 power
   Port 2: 0000.0100 power
   Port 3: 0000.0103 power enable connect
   Port 4: 0000.0103 power enable connect
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         0 Full speed (or root) hub
  bMaxPacketSize0        64
  bNumConfigurations      1
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0001
  Self Powered


FireFly USB HUB (does not work well when mixing HS and FS/LS devices)
-----------------------

$ lsusb -t
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=dwc2/1p, 480M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=dwc2/1p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M
        |__ Port 1: Dev 3, If 0, Class=Vendor Specific Class, Driver=, 480M
        |__ Port 3: Dev 4, If 0, Class=Audio, Driver=snd-usb-audio, 12M
        |__ Port 3: Dev 4, If 1, Class=Audio, Driver=snd-usb-audio, 12M

$ lsusb -d 1a40:0101 -v

Bus 001 Device 002: ID 1a40:0101 Terminus Technology Inc. Hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         2 TT per port
  bMaxPacketSize0        64
  idVendor           0x1a40 Terminus Technology Inc.
  idProduct          0x0101 Hub
  bcdDevice            1.00
  iManufacturer           0
  iProduct                1 USB 2.0 Hub [MTT]
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           41
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      1 Single TT
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0001  1x 1 bytes
        bInterval              12
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      2 TT per port
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0001  1x 1 bytes
        bInterval              12
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             4
  wHubCharacteristic 0x0080
    Ganged power switching
    Ganged overcurrent protection
    TT think time 8 FS bits
    Port indicators
  bPwrOn2PwrGood       50 * 2 milli seconds
  bHubContrCurrent    100 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0xff
 Hub Port Status:
   Port 1: 0000.0503 highspeed power enable connect
   Port 2: 0000.0100 power
   Port 3: 0000.0103 power enable connect
   Port 4: 0000.0100 power
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         0 Full speed (or root) hub
  bMaxPacketSize0        64
  bNumConfigurations      1
can't get debug descriptor: Resource temporarily unavailable
Device Status:     0x0001
  Self Powered

-- 
Med Vänliga Hälsningar / Best Regards

Mirza Krak

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