Hi, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes: > On Thu, 12 Nov 2015, Felipe Balbi wrote: > >> Hi, >> >> Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes: >> > [Adding linux-usb to the CC list] >> > >> > On Wed, 11 Nov 2015, Douglas Gilbert wrote: >> > >> >> Hi, >> >> I have been running into problems trying to use a USB device port >> >> on an Acme System's Arietta G25 (Atmel at91sam9g25 hence at91sam9x5 >> >> family in the kernel) as a USB mass storage gadget. Since the problem >> >> may be anywhere in the stack, I have sent this post to a USB expert >> >> as well as at91sam9x5 experts. >> >> >> >> In all cases the mass storage device appears on the host system >> >> after I do 'modprobe g_mass_storage file=/tmp/backing_file' on the >> >> Arietta G25: >> >> >> >> # lsscsi >> >> [0:0:0:0] disk ATA INTEL SSDSC2BW18 DC32 /dev/sda >> >> [6:0:0:0] disk Linux File-Stor Gadget 0400 /dev/sdb >> >> >> >> However if the host port is USB 3.0 (e.g. on my Lenovo >> >> X240 laptop) and the kernel is in the 4.0 series then all attempts >> > >> > You mean if the _gadget's_ kernel is >= 4.0, right? Not the host's >> > kernel. >> > >> >> by the host to read data fail on that mass storage gadget. >> >> For example, I see lots of this in my syslog: >> >> >> >> sd 6:0:0:0: [sdb] >> >> Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK >> >> sd 6:0:0:0: [sdb] CDB: >> >> Read(10): 28 00 00 00 00 00 00 00 08 00 >> >> end_request: I/O error, dev sdb, sector 0 >> >> Buffer I/O error on device sdb, logical block 0 >> >> usb 2-2: reset high-speed USB device number 9 using xhci_hcd >> >> xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep >> >> ffff8800ae58f180 >> >> xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep >> >> ffff8800ae58f1c0 >> >> ... >> >> >> >> I have tried around 6 different kernels in the lk 3.19 to lk 4.3.0 >> >> on the mass storage gadget (Arietta) with 3.19 works while lk 4.0.0-rc4 >> >> is the lowest (in my sample) that fails. My host system is Ubuntu 14.04 >> >> with either its stock kernel (3.13.0-68-generic) or my own hand built >> >> lk 4.3.0; both react the same way to this problem. >> >> >> >> Attached are the outputs of 'lsusb -v' for that mass storage gadget as >> >> seen on the host system. The "319" works while the other two fail. One >> >> difference is that wMaxPacketSize is 512 bytes for "319" and 64 bytes >> >> for the other two. Is that significant? [The block size on most >> >> storage devices is typically 512 bytes.] >> > >> > That most certainly _is_ significant. Almost nothing will work right >> > if the maxpacket size is wrong. >> >> sounds like this gadget is using FS ? > > No. See this line from above: > >> >> usb 2-2: reset high-speed USB device number 9 using xhci_hcd > >> >> Also, my problem seems to be sensitive to the host port being USB >> >> 3.0 since I have an older Lenovo X201 with USB 2.0 ports that does >> >> _not_ exhibit this problem. IOW when I connect my Arietta G25 mass >> >> storage gadget to the X201, it works properly for all G25 kernels >> >> that I have tried. >> >> >> >> >> >> Also tested a W7 host box with both USB 2.0 and USB 3.0 host ports >> >> and my mass storage gadget worked properly with lk 4.0.0-rc4 on >> >> both 2.0 and 3.0 ports. The Device Manager in W7 shows that it has >> >> xHCI driver present. >> > >> > I don't know what's going on with Windows, but this seems like a bug in >> > either the at91sam9g25 UDC driver or the composite gadget core. >> >> I'd blame UDC driver. We have several other UDCs working with the same >> configuration. > > Sounds reasonable to me. But that doesn't explain why it works okay > with the older Lenovo X201 laptop. it seems like only x240 is running > 4.0. What is x201 running ? Could be older, buggy xhci driver. -- balbi
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