linux/drivers/usb
Sarah Sharp 159e1fcc9a xhci: Don't write zeroed pointers to xHC registers.
When xhci_mem_cleanup() is called, we can't be sure if the xHC is
actually halted.  We can ask the xHC to halt by writing to the RUN bit
in the command register, but that might timeout due to a HW hang.

If the host controller is still running, we should not write zeroed
values to the event ring dequeue pointers or base tables, the DCBAA
pointers, or the command ring pointers.  Eric Fu reports his VIA VL800
host accesses the event ring pointers after a failed register restore on
resume from suspend.  The hypothesis is that the host never actually
halted before the register write to change the event ring pointer to
zero.

Remove all writes of zeroed values to pointer registers in
xhci_mem_cleanup().  Instead, make all callers of the function reset the
host controller first, which will reset those registers to zero.
xhci_mem_init() is the only caller that doesn't first halt and reset the
host controller before calling xhci_mem_cleanup().

This should be backported to kernels as old as 2.6.32.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: Elric Fu <elricfu1@gmail.com>
Cc: stable@vger.kernel.org
2012-04-11 08:28:55 -07:00
..
atm module_param: make bool parameters really bool (drivers & misc) 2012-01-13 09:32:20 +10:30
c67x00 usb: convert drivers/usb/* to use module_platform_driver() 2011-11-28 06:48:32 +09:00
class USB merge for 3.4-rc1 2012-03-20 11:26:30 -07:00
core USB: fix race between root-hub suspend and remote wakeup 2012-04-09 15:43:21 -07:00
dwc3 USB merge for 3.4-rc1 2012-03-20 11:26:30 -07:00
early
gadget Merge 3.2-rc1 into usb-linus 2012-04-08 08:26:51 -07:00
host xhci: Don't write zeroed pointers to xHC registers. 2012-04-11 08:28:55 -07:00
image USB: convert drivers/usb/* to use module_usb_driver() 2011-11-18 09:34:02 -08:00
misc USB: usbsevseg: fix max length 2012-01-24 12:08:36 -08:00
mon usb: Add export.h for EXPORT_SYMBOL/THIS_MODULE where needed 2011-10-31 19:31:25 -04:00
musb Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-03-29 15:34:57 -07:00
otg usb: otg: ab8500-usb: make probe() work again 2012-03-02 16:22:11 -08:00
renesas_usbhs Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-03-29 15:34:57 -07:00
serial USB: serial: fix race between probe and open 2012-04-10 13:35:53 -07:00
storage usb: storage: fix lockdep warning inside usb_stor_pre_reset(v2) 2012-04-06 13:54:00 -07:00
wusbcore uwb & wusb: fix kconfig error 2012-01-26 11:22:42 -08:00
Kconfig usb: Put USB Kconfig items back under USB. 2012-04-06 13:37:21 -07:00
Makefile USB: OTG should be linked before Host 2011-11-26 19:58:47 -08:00
README
usb-common.c usb: Provide usb_speed_string() function 2011-09-18 01:29:04 -07:00
usb-skeleton.c Revert "USB: usb-skeleton.c: fix open/disconnect race" 2012-01-24 12:02:38 -08:00

README

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 ("khubd").

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.