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    SubjectRe: [PATCH] usb: gadget: f_fs: Fix kernel panic for SuperSpeed
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    On 2016年04月26日 16:49, Jim Lin wrote:
    > On 2016年04月25日 20:01, Felipe Balbi wrote:
    >> * PGP Signed by an unknown key
    >>
    >>
    >>
    >>
    >>>> Is this happening on set_config() ? If that's the case, why is
    >>>> gadget->speed set to USB_SPEED_SUPER to start with ? Your controller
    >>>> should already have negotiated highspeed which means
    >>>> function_descriptors() should have returned highspeed descriptors,
    >>>> not a
    >>>> NULL superspeed.
    >>>>
    >>>> Care to explain why you haven't negotiated Highspeed ? The only
    >>>> thing I
    >>>> can think of is that you're using a Superspeed-capable peripheral
    >>>> controller (dwc3?) with maximum-speed set to Superspeed, with a
    >>>> Superspeed-capable cable connected to an XHCI PC, but loading a
    >>>> high-speed gadget driver (which you got from Android, written with
    >>>> f_fs)
    >>>> and this gadget doesn't tell composite that its maximum speed is
    >>>> Highspeed, instead of super-speed.
    >>>>
    >>>> We can add a check, sure, to avoid a kernel oops; however, you should
    >>>> really fix up the gadget implementation and/or set dwc3's
    >>>> maximum-speed
    >>>> property accordingly.
    >>>>
    >>>> Can you check if this patch makes your scenario work while still being
    >>>> fully functional ?
    >>>>
    >>>> diff --git a/drivers/usb/gadget/composite.c
    >>>> b/drivers/usb/gadget/composite.c
    >>>> index de9ffd60fcfa..3d3cdc5ed20d 100644
    >>>> --- a/drivers/usb/gadget/composite.c
    >>>> +++ b/drivers/usb/gadget/composite.c
    >>>> @@ -66,20 +66,36 @@ function_descriptors(struct usb_function *f,
    >>>> {
    >>>> struct usb_descriptor_header **descriptors;
    >>>> + /*
    >>>> + * NOTE: we try to help gadget drivers which might not be setting
    >>>> + * max_speed appropriately.
    >>>> + */
    >>>> +
    >>>> switch (speed) {
    >>>> case USB_SPEED_SUPER_PLUS:
    >>>> descriptors = f->ssp_descriptors;
    >>>> - break;
    >>>> + if (descriptors)
    >>>> + break;
    >>>> + /* FALLTHROUGH */
    >>>> case USB_SPEED_SUPER:
    >>>> descriptors = f->ss_descriptors;
    >>>> - break;
    >>>> + if (descriptors)
    >>>> + break;
    >>>> + /* FALLTHROUGH */
    >>>> case USB_SPEED_HIGH:
    >>>> descriptors = f->hs_descriptors;
    >>>> - break;
    >>>> + if (descriptors)
    >>>> + break;
    >>>> + /* FALLTHROUGH */
    >>>> default:
    >>>> descriptors = f->fs_descriptors;
    >>>> }
    >>>> + /*
    >>>> + * if we can't find any descriptors at all, then this gadget
    >>>> deserves to
    >>>> + * Oops with a NULL pointer dereference
    >>>> + */
    >>>> +
    >>>> return descriptors;
    >>>> }
    >>> After trying your change, no kernel panic, but SuperSpeed device
    >>> (device
    >>> mode) is not enumerated by ubuntu 14.04 USB 3.0 host controller as MTP
    >>> device with USB3.0 cable.
    >> what do you get on dmesg on host side ? Are you running dwc3 ? If you
    >> are, please capture trace logs of the failure:
    >>
    >> # mount -t debugfs none /sys/kernel/debug
    >> # cd /sys/kernel/debug/tracing
    >> # echo 2048 > buffer_size_kb
    >> # echo 1 > events/dwc3/enable
    >>
    >> (now connect your cable to host pc)
    >>
    >> # cp trace /path/to/non-volatile/storage/trace.txt
    >>
    >> Please reply with this trace.txt file and dmesg from host side.
    > This is not running with dwc3.
    >
    > dmesg from PC host side (after adding your change without my patch):
    >
    > [17907.984647] usb 6-2: new SuperSpeed USB device number 54 using
    > xhci_hcd
    > [17908.012036] usb 6-2: No SuperSpeed endpoint companion for config 1
    > interface 1 altsetting 0 ep 2: using minimum values
    > [17908.012040] usb 6-2: No SuperSpeed endpoint companion for config 1
    > interface 1 altsetting 0 ep 131: using minimum values
    > [17908.013652] usb 6-2: New USB device found, idVendor=xxxx,
    > idProduct=xxxx
    > [17908.013656] usb 6-2: New USB device strings: Mfr=1, Product=2,
    > SerialNumber=3
    > [17908.013658] usb 6-2: Product: xxxxxxx
    > [17908.013661] usb 6-2: Manufacturer: xxxxxx
    > [17908.013664] usb 6-2: SerialNumber: 1234567890
    > [17908.014680] xhci_hcd 0000:05:00.0: ERROR: unexpected command
    > completion code 0x11.
    > [17908.014690] usb 6-2: can't set config #1, error -22
    >
    > I also attach git log of system/core/adb/usb_linux_client.cpp of
    > Android N for your reference.
    > "
    > Author: Badhri Jagan Sridharan <Badhri@google.com>
    > Date: Mon Oct 5 13:04:03 2015 -0700
    >
    > adbd: Add os descriptor support for adb.
    >
    > Eventhough windows does not rely on extended os
    > descriptor for adbd, when android usb device is
    > configures as a composite device such as mtp+adb,
    > windows discards the extended os descriptor even
    > if one of the USB function fails to send
    > the extended compat descriptor. This results in automatic
    > install of MTP driverto fail when Android device is in
    > "File Transfer" mode with adb enabled.
    >
    > https://msdn.microsoft.com/en-us/library/windows/hardware/gg463179.aspx
    > "
    >
    How do we proceed on this patch?
    [PATCH] usb: gadget: f_fs: Fix kernel panic for SuperSpeed

    Thanks,
    --nvpublic

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