Hi
We are using Texas Instruments TUSB73x0 SuperSpeed USB 3.0 xHCI Host Controller (rev 02). each xHCI HC connect to 3 USB camera directly.
Camera 1: 1200*1200*16*30 = 691200000b/s ~ 700Mb/s
Camera 2: 1200*1200*16*30 = 691200000b/s ~ 700Mb/s
Camera 3: 1920*1200*16*20 = 737280000b/s ~ 740Mb/s
1200 x 1200 or 1920 x 1200 are picture resolution(number of pixel for each picture).
16 is YUV encoding, each pixel needs 16bit.
30/20 are frame rate.
if we using bulk transaction. some times we got following error from kernel message, it is not easy to reproduce, but we got those error from time to time.
[Thu Apr 6 20:28:53 2023] uvcvideo: Non-zero status (-71) in video completion handler. [Thu Apr 6 20:28:53 2023] xhci_hcd 0000:77:00.0: Transfer error for slot 2 ep 6 on endpoint [Thu Apr 6 20:28:53 2023] uvcvideo: Non-zero status (-71) in video completion handler. [Thu Apr 6 20:28:53 2023] xhci_hcd 0000:77:00.0: Transfer error for slot 2 ep 6 on endpoint
those error msg from this kernel code:
Do you have any idea what this error means? what can we do to avoid those errors?
If we change camera to use isochronous transaction. we can only enable one isochronous camera.
from 2nd USB camera, will get following error.
usb 10-2: Not enough bandwidth for new device state. usb 10-2: Not enough bandwidth for altsetting 1
Detail logs.
[176505.200808] uvcvideo: Device requested 46080 B/frame bandwidth. [176505.200811] uvcvideo: Selecting alternate setting 1 (46080 B/frame bandwidth). [176505.200812] uvcvideo: Device requested 46080 B/frame bandwidth. [176505.200814] uvcvideo: Selecting alternate setting 1 (46080 B/frame bandwidth). [176505.200860] xhci_hcd 0000:49:00.0: add ep 0x83, slot id 3, new drop flags = 0x0, new add flags = 0x81 [176505.200864] xhci_hcd 0000:49:00.0: xhci_check_bandwidth called for udev 00000000dfb1a7cc [176505.200876] xhci_hcd 0000:49:00.0: // Ding dong! [176505.201309] xhci_hcd 0000:49:00.0: Successful Endpoint Configure command [176505.201469] xhci_hcd 0000:49:00.0: add ep 0x83, slot id 2, new drop flags = 0x0, new add flags = 0x81 [176505.201473] xhci_hcd 0000:49:00.0: xhci_check_bandwidth called for udev 000000004bbf2dcd [176505.201483] xhci_hcd 0000:49:00.0: // Ding dong! [176505.201542] usb 10-2: Not enough bandwidth for new device state. [176505.201547] xhci_hcd 0000:49:00.0: xhci_reset_bandwidth called for udev 000000004bbf2dcd [176505.201620] usb 10-2: Not enough bandwidth for altsetting 1 [176505.201625] xhci_hcd 0000:49:00.0: xhci_check_bandwidth called for udev 000000004bbf2dcd [176505.330084] xhci_hcd 0000:49:00.0: xhci_hub_status_data: stopping port polling. [176505.687380] uvcvideo: Allocated 64 URB buffers of 8x46080 bytes each. [176505.687615] xhci_hcd 0000:49:00.0: ERROR no room on ep ring, try ring expansion [176505.687629] xhci_hcd 0000:49:00.0: ring expansion succeed, now has 4 segments
I attached lsusb -v result here:
lsusb -d 04b4:1103 -v
Bus 012 Device 040: ID 04b4:1103 Cypress Semiconductor Corp.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 3.10
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2 ?
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 9
idVendor 0x04b4 Cypress Semiconductor Corp.
idProduct 0x1103
bcdDevice 0.00
iManufacturer 1
iProduct 2
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 218
bNumInterfaces 2
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 100mA
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 0
bInterfaceCount 2
bFunctionClass 14 Video
bFunctionSubClass 3 Video Interface Collection
bFunctionProtocol 0
iFunction 2
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 1 Video Control
bInterfaceProtocol 0
iInterface 2
VideoStreaming Interface Descriptor:
bLength 30
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 1
bmCapabilities 0x01
Still image supported
wWidth 1920
wHeight 1200
dwMinBitRate 737280000
dwMaxBitRate 737280000
dwMaxVideoFrameBufferSize 4608000
dwDefaultFrameInterval 1000000
bFrameIntervalType 1
dwFrameInterval( 0) 1000000
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 1
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0400 1x 1024 bytes
bInterval 1
bMaxBurst 14
Mult 2my question is:
USB 3.0 theoretical bandwidth is 5.0Gb/s, 10b/8b encoding, it's 4.0Gb/s. I understand there are some protocol overhead,
but each camera cost ~ 700Mbps, 3 camera total is < 3Gbps.
why we can not using isochronous for 3 camera?
is there any suggestion for improve stability of those 3 camera?
do you happen to have any benchmark result for TUSB73x0 that can share with us? thanks.
