1
linux/drivers/usb
Alan Stern e04f5f7e42 EHCI: fix direction handling for interrupt data toggles
This patch (as1480) fixes a rather obscure bug in ehci-hcd.  The
qh_update() routine needs to know the number and direction of the
endpoint corresponding to its QH argument.  The number can be taken
directly from the QH data structure, but the direction isn't stored
there.  The direction is taken instead from the first qTD linked to
the QH.

However, it turns out that for interrupt transfers, qh_update() gets
called before the qTDs are linked to the QH.  As a result, qh_update()
computes a bogus direction value, which messes up the endpoint toggle
handling.  Under the right combination of circumstances this causes
usb_reset_endpoint() not to work correctly, which causes packets to be
dropped and communications to fail.

Now, it's silly for the QH structure not to have direct access to all
the descriptor information for the corresponding endpoint.  Ultimately
it may get a pointer to the usb_host_endpoint structure; for now,
adding a copy of the direction flag solves the immediate problem.

This allows the Spyder2 color-calibration system (a low-speed USB
device that sends all its interrupt data packets with the toggle set
to 0 and hance requires constant use of usb_reset_endpoint) to work
when connected through a high-speed hub.  Thanks to Graeme Gill for
supplying the hardware that allowed me to track down this bug.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Graeme Gill <graeme@argyllcms.com>
CC: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-07-19 11:25:45 -07:00
..
atm drivers: usb: atm: ueagle-atm: Add missing const qualifier 2011-07-08 14:51:30 -07:00
c67x00 Fix common misspellings 2011-03-31 11:26:23 -03:00
class usb/class: use printk_ratelimited() instead of printk_ratelimit() 2011-07-01 14:43:24 -07:00
core Merge 3.0-rc2 into usb-linus as it's needed by some USB patches 2011-06-14 06:51:23 -07:00
early USB: EHCI: Support controllers with big endian capability regs 2011-05-03 11:43:21 -07:00
gadget Merge branch 'for-next' of master.kernel.org:/pub/scm/linux/kernel/git/balbi/usb into usb-next 2011-07-08 15:30:55 -07:00
host EHCI: fix direction handling for interrupt data toggles 2011-07-19 11:25:45 -07:00
image Fix common misspellings 2011-03-31 11:26:23 -03:00
misc Merge branch 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 2011-05-23 12:33:02 -07:00
mon USB: mon: Allow to use usbmon without debugfs 2011-07-08 14:55:09 -07:00
musb usb: musb: restore INDEX register in resume path 2011-07-08 12:47:25 +03:00
otg USB: OTG: Use work_queue in set_vbus for TWL6030 transciever 2011-07-01 14:45:43 -07:00
renesas_usbhs usb: renesas_usbhs: support multi driver 2011-07-08 15:08:19 -07:00
serial USB: serial: add IDs for WinChipHead USB->RS232 adapter 2011-07-19 04:48:45 -07:00
storage Realtek cr: Add autosuspend function. 2011-07-01 14:53:42 -07:00
wusbcore wusb: use printk_ratelimited() instead of printk_ratelimit() 2011-07-01 14:43:25 -07:00
Kconfig usb: renesas_usbhs: compile/config are rescued 2011-07-08 14:57:12 -07:00
Makefile USB: fix build of FSL MPH DR OF platform driver 2011-05-02 16:59:37 -07:00
README
usb-skeleton.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00

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.