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Mathias Nyman
219dcadc75
commitf068090426upstream. Ensure that the shared_hcd pointer is valid when calling usb_put_hcd() The shared_hcd is removed and freed in xhci by first calling usb_remove_hcd(xhci->shared_hcd), and later usb_put_hcd(xhci->shared_hcd) Afer commitfe190ed0d6("xhci: Do not halt the host until both HCD have disconnected their devices.") the shared_hcd was never properly put as xhci->shared_hcd was set to NULL before usb_put_hcd(xhci->shared_hcd) was called. shared_hcd (USB3) is removed before primary hcd (USB2). While removing the primary hcd we might need to handle xhci interrupts to cleanly remove last USB2 devices, therefore we need to set xhci->shared_hcd to NULL before removing the primary hcd to let xhci interrupt handler know shared_hcd is no longer available. xhci-plat.c, xhci-histb.c and xhci-mtk first create both their hcd's before adding them. so to keep the correct reverse removal order use a temporary shared_hcd variable for them. For more details see commit4ac53087d6("usb: xhci: plat: Create both HCDs before adding them") Fixes:fe190ed0d6("xhci: Do not halt the host until both HCD have disconnected their devices.") Cc: Joel Stanley <joel@jms.id.au> Cc: Chunfeng Yun <chunfeng.yun@mediatek.com> Cc: Thierry Reding <treding@nvidia.com> Cc: Jianguo Sun <sunjianguo1@huawei.com> Cc: <stable@vger.kernel.org> Reported-by: Jack Pham <jackp@codeaurora.org> Tested-by: Jack Pham <jackp@codeaurora.org> Tested-by: Peter Chen <peter.chen@nxp.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.