[cups] Cups-2.2.5 can't detect usb device

[HE Yanghui(alan)]

Hi,
I meet a strange issue.
I am porting CUPS-2.2.5 to mips-linux, but i can't see local printer on Web Interface when i try to "Add Printer". Then i use "lpinfo -v" under command line, there are some info output as below:
[3384:RG]# lpinfo -v
network ipp
network lpd
network http
network socket
[3384:RG]#
Similarly, we can't see any usb device.
However, When i execute CUPS backend program "usb", can see usb device info, as below:
[3384:RG]# /mnt/apps/lib/cups/backend/usb
direct usb://HP/Deskjet%205520%20series?serial=CN36A1665W05SW "HP Deskjet 5520 series" "HP Deskjet 5520 series" "MFG:HP;MDL:Deskjet 5520 series;
CMD:PCL3GUI,PCL3,PJL,JPEG,PCLM,AirPrint,DW-PCL,802.11,DESKJET,DYN;CLS:PRINTER;DES:CZ282B;CID:HPIJVIPAV2;LEDMDIS:USB#FF#CC#00,USB#07#01#02,USB#FF#04#01;IPP-HTTP:T;IPP-E:FF-CC-00,07-01-02,FF-04-01;eSCL:scan=FF-CC-00,07-01-02,FF-04-01,alt=07-01-02,FF-04-01,ver=1.9,rs=\"/eSCL\";SN:CN36A1665W05SW;S:038080C484201021005a0200000452801004428010046280100412b0014;Z:0102,05000009000001000001000001000001,0600,0700000000000000000000,0b000000000000000000009972000000009972000000009972000000009972,0c0,0e00000000000000000040,0f00000000000000001000,10000000000008000008000008000008,110,12000,150,17000000000000000000000000000055,181;" ""
[3384:RG]#

 Anybody has any think?

Thanks,
Alan

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