linux/drivers/usb
Dave Young f278a2f7bb tty: Fix regressions caused by commit b50989dc
The following commit made console open fails while booting:

	commit b50989dc44
	Author: Alan Cox <alan@linux.intel.com>
	Date:   Sat Sep 19 13:13:22 2009 -0700

	tty: make the kref destructor occur asynchronously

Due to tty release routines run in a workqueue now, error like the
following will be reported while booting:

INIT open /dev/console Input/output error

It also causes hibernation regression to appear as reported at
http://bugzilla.kernel.org/show_bug.cgi?id=14229

The reason is that now there's latency issue with closing, but when
we open a "closing not finished" tty, -EIO will be returned.

Fix it as per the following Alan's suggestion:

  Fun but it's actually not a bug and the fix is wrong in itself as
  the port may be closing but not yet being destructed, in which case
  it seems to do the wrong thing.  Opening a tty that is closing (and
  could be closing for long periods) is supposed to return -EIO.

  I suspect a better way to deal with this and keep the old console
  timing is to split tty->shutdown into two functions.

  tty->shutdown() - called synchronously just before we dump the tty
  onto the waitqueue for destruction

  tty->cleanup() - called when the destructor runs.

  We would then do the shutdown part which can occur in IRQ context
  fine, before queueing the rest of the release (from tty->magic = 0
  ...  the end) to occur asynchronously

  The USB update in -next would then need a call like

       if (tty->cleanup)
               tty->cleanup(tty);

  at the top of the async function and the USB shutdown to be split
  between shutdown and cleanup as the USB resource cleanup and final
  tidy cannot occur synchronously as it needs to sleep.

  In other words the logic becomes

       final kref put
               make object unfindable

       async
               clean it up

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
[ rjw: Rebased on top of 2.6.31-git, reworked the changelog. ]
Signed-off-by: "Rafael J. Wysocki" <rjw@sisk.pl>
[ Changed serial naming to match new rules, dropped tty_shutdown as per
  comments from Alan Stern  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-27 13:35:16 -07:00
..
atm firmware: atm/ueagle-atm: prepare for FIRMWARE_NAME_MAX removal 2009-06-15 21:30:24 -07:00
c67x00
class USB: fix USBTMC get_capabilities success handling 2009-09-23 06:46:39 -07:00
core USB: Add hub descriptor update hook for xHCI 2009-09-23 06:46:40 -07:00
early USB: ehci-dbgp: errata for EHCI debug/host controller synchronization 2009-09-23 06:46:38 -07:00
gadget headers: utsname.h redux 2009-09-23 18:13:10 -07:00
host Merge branch 'origin' into for-linus 2009-09-24 21:22:33 +01:00
image USB: remove unneeded printks from microtek driver 2009-09-23 06:46:34 -07:00
misc headers: kref.h redux 2009-09-26 10:17:19 -07:00
mon const: mark struct vm_struct_operations 2009-09-27 11:39:25 -07:00
musb USB: musb: fix put_device() call sequence 2009-09-23 06:46:33 -07:00
otg USB: OMAP: ISP1301: Compile fix 2009-09-23 06:46:37 -07:00
serial tty: Fix regressions caused by commit b50989dc 2009-09-27 13:35:16 -07:00
storage USB: unusual_devs.h: drop some unneeded floppy entries 2009-09-23 06:46:38 -07:00
wusbcore trivial: fix typos "man[ae]g?ment" -> "management" 2009-09-21 15:14:56 +02:00
Kconfig Merge branch 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze 2009-09-24 09:01:44 -07:00
Makefile USB: ehci,dbgp,early_printk: split ehci debug driver from early_printk.c 2009-09-23 06:46:38 -07:00
README
usb-skeleton.c USB: skeleton: fix coding style issues. 2009-09-23 06:46:40 -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.