9b481092c2
We've found that while in host mode, using Android, if one runs the command: stop adbd The existing usb devices being utilized in host mode are disconnected. This is most visible with usb networking devices. This seems to be due to adbd closing the file: /dev/usb-ffs/adb/ep0 Which calls ffs_ep0_release() and the following backtrace: [<ffffff800875a430>] dwc2_hsotg_ep_disable+0x148/0x150 [<ffffff800875a498>] dwc2_hsotg_udc_stop+0x60/0x110 [<ffffff8008787950>] usb_gadget_remove_driver+0x58/0x78 [<ffffff80087879e4>] usb_gadget_unregister_driver+0x74/0xe8 [<ffffff80087850c0>] unregister_gadget+0x28/0x58 [<ffffff800878511c>] unregister_gadget_item+0x2c/0x40 [<ffffff8008790ea8>] ffs_data_clear+0xe8/0xf8 [<ffffff8008790ed8>] ffs_data_reset+0x20/0x58 [<ffffff8008793218>] ffs_data_closed+0x98/0xe8 [<ffffff80087932d8>] ffs_ep0_release+0x20/0x30 Then when dwc2_hsotg_ep_disable() is called, we call kill_all_requests() which causes a bunch of the following messages: dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode dwc2 f72c0000.usb: Mode Mismatch Interrupt: currently in Host mode init: Service 'adbd' (pid 1915) killed by signal 9 init: Sending signal 9 to service 'adbd' (pid 1915) process group... init: Successfully killed process cgroup uid 0 pid 1915 in 0ms init: processing action (init.svc.adbd=stopped) from (/init.usb.configfs.rc:15) dwc2 f72c0000.usb: dwc2_hc_chhltd_intr_dma: Channel 8 - ChHltd set, but reason is unknown dwc2 f72c0000.usb: hcint 0x00000002, intsts 0x04200029 dwc2 f72c0000.usb: dwc2_hc_chhltd_intr_dma: Channel 12 - ChHltd set, but reason is unknown dwc2 f72c0000.usb: hcint 0x00000002, intsts 0x04200029 dwc2 f72c0000.usb: dwc2_hc_chhltd_intr_dma: Channel 15 - ChHltd set, but reason is unknown dwc2 f72c0000.usb: hcint 0x00000002, intsts 0x04200029 dwc2 f72c0000.usb: dwc2_hc_chhltd_intr_dma: Channel 3 - ChHltd set, but reason is unknown dwc2 f72c0000.usb: hcint 0x00000002, intsts 0x04200029 dwc2 f72c0000.usb: dwc2_hc_chhltd_intr_dma: Channel 4 - ChHltd set, but reason is unknown dwc2 f72c0000.usb: hcint 0x00000002, intsts 0x04200029 dwc2 f72c0000.usb: dwc2_update_urb_state_abn(): trimming xfer length And the usb devices connected are basically hung at this point. It seems like if we're in host mode, we probably shouldn't run the dwc2_hostg_ep_disable logic, so this patch returns an error in that case. With this patch (along with the previous patch in this set), we avoid the mismatched interrupts and connected usb devices continue to function. I'm not sure if some other solution would be better here, but this seems to work, so I wanted to send it out for input on what the right approach should be. Cc: Wei Xu <xuwei5@hisilicon.com> Cc: Guodong Xu <guodong.xu@linaro.org> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: YongQin Liu <yongqin.liu@linaro.org> Cc: John Youn <johnyoun@synopsys.com> Cc: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> Cc: Douglas Anderson <dianders@chromium.org> Cc: Chen Yu <chenyu56@huawei.com> Cc: Felipe Balbi <felipe.balbi@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-usb@vger.kernel.org Acked-by: Minas Harutyunyan <hminas@synopsys.com> Tested-by: Minas Harutyunyan <hminas@synopsys.com> Reported-by: YongQin Liu <yongqin.liu@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("hub_wq").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.