i.MX8MPlus: USB Mass Storage (Lexar 3.0) works sometimes

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i.MX8MPlus: USB Mass Storage (Lexar 3.0) works sometimes

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ransar
Contributor I

Hi,

The Lexar 3.0 USB mass storage on i.mx8mplus works sometimes with different behavior. Other USB devices like SanDisk, Samsung and Transcend works fine everytime. However Lexar 3.0 works sometimes in a particular scenarios like if we plug-in the USB device first and then boot the board, it works fine. But if we plug USB device after booting the board, it will get detected and work around 2 out of 10 times. The testing logs are attached here.
One difference is seen in MxPwr value for Lexar USB device and other devices. Logs are below for usb-devices command.
Lexar 3.0 USB

T:  Bus=01 Lev=01 Prnt=01 Port=09 Cnt=01 Dev#= 41 Spd=480 MxCh= 0
D:  Ver= 2.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=05dc ProdID=a838 Rev=11.00
S:  Manufacturer=Lexar
S:  Product=USB Flash Drive
S:  SerialNumber=AA14IYGKVI0QF18L
C:  #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=500mA
I:  If#=0x0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage

SanDisk USB

T:  Bus=01 Lev=01 Prnt=01 Port=09 Cnt=01 Dev#= 42 Spd=480 MxCh= 0
D:  Ver= 2.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=0781 ProdID=5581 Rev=01.00
S:  Manufacturer=SanDisk
S:  Product=Ultra
S:  SerialNumber=4C530001191203121182
C:  #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=224mA
I:  If#=0x0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage

Transcend USB

T: Bus=02 Lev=01 Prnt=01 Port=04 Cnt=01 Dev#= 2 Spd=5000 MxCh= 0
D: Ver= 3.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 9 #Cfgs= 1
P: Vendor=8564 ProdID=1000 Rev=11.00
S: Manufacturer=JetFlash
S: Product=Mass Storage Device
S: SerialNumber=05CO5Z9ZYSBL9NDC
C: #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=304mA
I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage

Here the MxPwr value is highest for Lexar USB. This may be a clue for the problem.

Thanks,
Ansar Rasool

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