linux.git/drivers/usb/core/hcd.c, branch v2.6.22

USB: replace flush_workqueue with cancel_sync_work

2007-05-29T20:39:07+00:00

This patch (as912) replaces a couple of calls to flush_workqueue()
with cancel_sync_work() and cancel_rearming_delayed_work().  Using a
more directed approach allows us to avoid some nasty deadlocks.  The
prime example occurs when a first-level device (the parent is a root
hub) is removed while at the same time the root hub gets a remote
wakeup request.  khubd would try to flush the autosuspend workqueue
while holding the root-hub's lock, and the remote-wakeup workqueue
routine would be waiting to lock the root hub.

The patch also reorganizes the power management portion of
usb_disconnect(), separating it out into its own routine.  The
autosuspend workqueue entry is cancelled immediately instead of
waiting for the device's release routine.  In addition,
synchronization with the autosuspend thread is carried out even for
root hubs (an oversight in the original code).

Signed-off-by: Alan Stern 
Cc: Andrew Morton 
Cc: Greg KH 
Cc: Mark Lord 
Signed-off-by: Linus Torvalds

USB: Deref URB after usbmon is done with it

2007-05-23T06:45:49+00:00

I haven't personally run across an oops because of this, but I feel safer
with this fix in place.

Signed-off-by: Pete Zaitcev 
Signed-off-by: Greg Kroah-Hartman

USB: remove unneeded WARN_ON

2007-05-23T06:45:49+00:00

This patch (as883) removes an out-of-date WARN_ON from the main HCD
endpoint-disable routine.  The warning is triggered whenever an
endpoint is disabled while the root hub is suspended.  In the past
that may not have been legal, but it definitely is legal now.  Merely
unbinding a USB driver will do it.

Furthermore, I've never seen any occurrences of this warning that
really did signal an actual bug or error condition.  At this point it
has outlived its purpose.

Signed-off-by: Alan Stern 
Signed-off-by: David Brownell

USB: add "last_busy" field for use in autosuspend

2007-04-27T20:28:39+00:00

This patch (as877) adds a "last_busy" field to struct usb_device, for
use by the autosuspend framework.  Now if an autosuspend call comes at
a time when the device isn't busy but hasn't yet been idle for long
enough, the timer can be set to exactly the desired value.  And we
will be ready to handle things like HID drivers, which can't maintain
a useful usage count and must rely on the time-of-last-use to decide
when to autosuspend.

The patch also makes some related minor improvements:

	Move the calls to the autosuspend condition-checking routine
	into usb_suspend_both(), which is the only place where it
	really matters.

	If the autosuspend timer is already running, don't stop
	and restart it.

	Replace immediate returns with gotos so that the optional
	debugging ouput won't be bypassed.

	If autoresume is disabled but the device is already awake,
	don't return an error for an autoresume call.

	Don't try to autoresume a device if it isn't suspended.
	(Yes, this undercuts the previous change -- so sue me.)

	Don't duplicate existing code in the autosuspend work routine.

	Fix the kerneldoc in usb_autopm_put_interface(): If an
	autoresume call fails, the usage counter is left unchanged.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: separate autosuspend from external suspend

2007-04-27T20:28:35+00:00

This patch (as866) adds new entry points for external USB device
suspend and resume requests, as opposed to internally-generated
autosuspend or autoresume.  It also changes the existing
remote-wakeup code paths to use the new routines, since remote wakeup
is not the same as autoresume.

As part of the change, it turns out to be necessary to do remote
wakeup of root hubs from a workqueue.  We had been using khubd, but it
does autoresume rather than an external resume.  Using the
ksuspend_usb_wq workqueue for this purpose seemed a logical choice.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

USB: fix race in HCD removal

2007-04-27T20:28:34+00:00

This patch (as865) fixes a race in the HCD removal code discovered by
Milan Plzik.  Arrival of an interrupt after the root hub was
unregistered could cause the root-hub status timer to start up, even
after it was supposed to have been shut down.  The problem is fixed by
moving the del_timer_sync() call to after the HCD's stop() method, at
which time IRQ generation should be disabled.

Cc: Milan Plzik 
Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

usbcore: remove unused bandwith-related code

2007-02-07T23:44:37+00:00

This patch (as841) removes from usbcore a couple of support routines
meant to help with bandwidth allocation.  With the changes to uhci-hcd
in the previous patch, these routines are no longer used anywhere.
Also removed is the CONFIG_USB_BANDWIDTH option; it no longer does
anything and is no longer needed since the HCDs now handle bandwidth
issues correctly.

Signed-off-by: Alan Stern 
Signed-off-by: David Brownell 
Signed-off-by: Greg Kroah-Hartman

usb hub: fix root hub code so it takes more than 15 devices per root hub

2006-12-01T22:23:26+00:00

Wireless USB Host Controllers accept a large number of devices per
host, which shows up as a large number of ports in its root hub.

When the number of ports in a hub device goes over 16, the activation
of the hub fails with the cryptic message in klogd.

hub 2-0:1.0: activate --> -22

Following this further, it was seen that:

hub_probe()
  hub_configure()
    generates pipe number

    pseudo allocates buffer 'maxp' bytes in size using usb_maxpacket()

      The endpoint descriptor for a root hub interrupt endpoint is
      declared in
      drivers/usb/core/hcd.c:hs_rh_config_descriptor and declares it
      to be size two (supporting 15 devices max).

    hub_activate()
      usb_hcd_submit_urb()
        rh_urb_enqueue()
          urb->pipe is neither int nor ctl, so it errors out
            rh_queue_status()
              Returns -EINVAL because the buffer length is smaller
              than the minimum needed to report all the hub port
              bits as in accordance with USB2.0[11.12.3]. There has
              to be trunc((PORTS + 1 + 7) / 8) bytes of space at
              least.

Alan Stern confirmed that the reason for reading maxpktsize and not
the right amount is because some hubs are known to return more data
and thus cause overflow. 

So this patch simply changes the code to make the interrupt endpoint's
max packet size be at least the minimum required by USB_MAXCHILDREN
(instead of a fixed magic number) and add documentation for that. This
way we are always ahead of the limit.

Signed-off-by: Inaky Perez-Gonzalez 
Signed-off-by: Greg Kroah-Hartman

IRQ: Maintain regs pointer globally rather than passing to IRQ handlers

2006-10-05T14:10:12+00:00

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells 
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

[PATCH] namespaces: utsname: use init_utsname when appropriate

2006-10-02T14:57:21+00:00

In some places, particularly drivers and __init code, the init utsns is the
appropriate one to use.  This patch replaces those with a the init_utsname
helper.

Changes: Removed several uses of init_utsname().  Hope I picked all the
	right ones in net/ipv4/ipconfig.c.  These are now changed to
	utsname() (the per-process namespace utsname) in the previous
	patch (2/7)

[akpm@osdl.org: CIFS fix]
Signed-off-by: Serge E. Hallyn 
Cc: Kirill Korotaev 
Cc: "Eric W. Biederman" 
Cc: Herbert Poetzl 
Cc: Andrey Savochkin 
Cc: Serge Hallyn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds