1
linux/drivers/usb
Sarah Sharp 6cc30d85a5 USB: xHCI: Fix bug in link TRB activation change.
Commit 6c12db90f1 introduced a bug for
control transfers.  The patch was supposed to change when the link TRBs at
the end of each ring segment were given to the hardware.  If a transfer
descriptor (TD) ended just before the link TRB, the code wouldn't give
back the link TRB to the hardware; instead it would be given back in
prepare_ring() just before the next TD was enqueued at the top of the
ring.

Unfortunately, the code relied on checking the chain bit of the TRB to
determine whether the TD ended just before the link TRB.  It assumed that
the ring enqueuing code would call prepare_ring() before enqueuing the
next TD.  However, control transfers are made of multiple TDs, and
prepare_ring() is only called once before enqueuing two or three TDs.

If the first or second TD of the control transfer ended just before the
link TRB, then the code in inc_enq() would not move the enqueue pointer
past the link TRB, and the link TRB would get overwritten.  This would
cause the xHCI driver to start writing to memory past the ring segment,
and eventually the system would crash or hang.

The fix is to add a flag to inc_enq() that says whether the caller will
enqueue more TDs before calling prepare_ring().  If the chain bit is
cleared (meaning this is the last TRB in a TD), and the caller will not
enqueue more TDs, then we defer giving back the link TRB.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-06-30 08:16:05 -07:00
..
atm usb: atm: speedtch: use new hex_to_bin() method 2010-05-25 08:07:05 -07:00
c67x00 USB: make hcd.h public (drivers dependency) 2010-05-20 13:21:30 -07:00
class USB: cdc-acm: fix resource reclaim in error path of acm_probe 2010-06-04 13:16:19 -07:00
core USB: unbind all interfaces before rebinding them 2010-06-04 13:16:20 -07:00
early echi-dbgp: Add kernel debugger support for the usb debug port 2010-05-20 21:04:31 -05:00
gadget USB: gadget: g_fs: possible invalid pointer reference bug fixed 2010-06-30 08:16:05 -07:00
host USB: xHCI: Fix bug in link TRB activation change. 2010-06-30 08:16:05 -07:00
image USB: BKL removal: mdc800 2010-03-02 14:54:27 -08:00
misc usb: sisusb_con.c: fix shadows sparse warning 2010-05-20 13:21:41 -07:00
mon Merge branch 'bkl/ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing 2010-05-24 08:01:10 -07:00
musb usb: musb: update gfp/slab.h includes 2010-05-20 13:21:50 -07:00
otg USB: omap: switch to subsys_initcall for isp1301 transceiver 2010-05-20 13:21:38 -07:00
serial USB: serial: digi_acceleport: Eliminate a NULL pointer dereference 2010-06-04 13:16:19 -07:00
storage usb-storage: always print quirks 2010-05-20 13:21:49 -07:00
wusbcore Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 2010-05-20 21:26:12 -07:00
Kconfig Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 2010-03-03 08:48:58 -08:00
Makefile USB: MXC: Add i.MX21 specific USB host controller driver. 2010-03-02 14:52:55 -08:00
README
usb-skeleton.c USB: rename usb_buffer_alloc() and usb_buffer_free() users 2010-05-20 13:21:38 -07:00

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.