Hi, Bin Liu <b-liu@xxxxxx> writes: > Hi, > > On 10/13/2015 01:22 PM, Felipe Balbi wrote: >> Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> writes: >>> On Mon, Oct 12, 2015 at 11:34 AM, Yegor Yefremov >>> <yegorslists@xxxxxxxxxxxxxx> wrote: >>>> We have a problem, when using more than 12 FTDI ports. Kernels tried: >>>> 3.18.1, 4.2.3 and 4.3-rc5. SoC am335x 600MHz >>>> >>>> Below the USB topology: >>>> >>>> # lsusb -t >>>> /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=musb-hdrc/1p, 480M >>>> /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=musb-hdrc/1p, 480M >>>> |__ Port 1: Dev 2, If 0, Class=, Driver=hub/4p, 480M >>>> |__ Port 1: Dev 9, If 0, Class=, Driver=hub/4p, 480M >>>> |__ Port 1: Dev 10, If 0, Class=, Driver=ftdi_sio, 12M >>>> |__ Port 2: Dev 11, If 0, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 2: Dev 11, If 1, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 2: Dev 11, If 2, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 2: Dev 11, If 3, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 12, If 0, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 12, If 1, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 12, If 2, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 12, If 3, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 2: Dev 4, If 0, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 2: Dev 4, If 1, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 2: Dev 4, If 2, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 2: Dev 4, If 3, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 7, If 0, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 7, If 1, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 7, If 2, Class=, Driver=ftdi_sio, 480M >>>> |__ Port 3: Dev 7, If 3, Class=, Driver=ftdi_sio, 480M > > How many EPs does each FTDI device require? at least one INT EP, right? > If I read it right, the topology above has 2 hubs, and 16 high-speed > FTDI and 1 full-speed FTDI. So it requires at least 18 high-speed INT > EPs. MUSB driver only has 11 high-speed EPs for mode-4 which is the EP > configuration used by default. I am wondering how those devices got > enumerated properly. dynamic EP allocation, but that has its own limitations. -- balbi
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