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 ? >> 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. -- balbi
Attachment:
signature.asc
Description: PGP signature
