Hi,
Our customer is building a custom board using AM4378.
They are running Linux SDK Ver 07.03.00.005 with modifications on that board.
They want to use the USB interface on that board at full speed (12Mbps) fixed.
They have modified arch/arm/dts/am437x-gp-evm.dts as follows
&usb1 { dr_mode = "host"; status = "okay"; maximum-speed = "full-speed"; // appended }; &usb2 { dr_mode = "host"; status = "okay"; maximum-speed = "full-speed"; // appended };
But when they looked at it with the lsusb command (the port they inserted the USB3 memory into) it was 480Mbps.
root@am437x-evm:~# lsusb -t /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 5000M /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 480M /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 5000M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 480M |__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 480M <-attach USB3 storage
What can they do to limit the USB speed to 12Mbps?
Best Regards,
Kouji Nishigata