Add modem portion of USB device labeled:
Model iCON 210, Qualcomm 3G HSDPA, designed in EU by Option

Device starts in usb-storage mode (1e0e:f000) and requires the use of a tool
like usb_modeswitch to switch it to modem mode (1e0e:9000).
Signed-off-by: NKai Engert <kaie@kuix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The isp1760_plat_remove function is declared with __devexit, so the
.remove assignment needs to be wrapped with __devexit_p().
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This is an update to the "usb-ehci-update-toggle-state-for-linked-qhs"
patch.  Since an HCD's endpoint_reset method can be called in
interrupt context, it mustn't assume that interrupts are enabled or
that it can sleep.

So we revert to the original way of refreshing QHs' toggle bits.  Now
the endpoint_reset method merely clears the toggle flag in the device
structure (as was done before) and starts an async QH unlink.  When the
QH is linked again, after the unlink finishes and an URB is queued,
the qh_refresh() routine will update the QH's toggle bit.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NDavid <david@unsolicited.net>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

FHCI_PORT_DISABLED, -LOW and -FULL are mutually exclusive as status.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The product ID's for the following devices have been added:
- LOAD-n-GO
- ICD-U64
- PRIME-8
Signed-off-by: NJan Capek <jan@ccsinfo.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Move USB_GADGET_IMX to the right section of Kconfig as this
controller is available only as integrated on i.MX CPU.
Signed-off-by: NPaulius Zaleckas <paulius.zaleckas@teltonika.lt>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

I recently bought a PC interface for the Cressi Edy dive computer
(www.cressi.it) and discovered that it uses the pl2303 chip, albeit
with ad-hoc vendor and product ids (04b8, 0521 respectively). Being in
the process of writing a linux software for such device (cressi only
provides a windows software), I patched the pl2303 linux driver to
have the interface recognized. I am submitting you the patch (very
basic) for inclusion in next kernel version.

From: Gianpaolo Cugola <gianpaoloc@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

PL2303 has private data shovelling methods that also have no fast path. Fix
them to work the same way as the default handler.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The sysrq code acquired a kref leak. Fix it by passing the tty separately
from the caller (thus effectively using the callers kref which all the
callers hold anyway)
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We can't go around calling all sorts of magic per character functions at
full rate 3G data speed.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 5fd29d6c ("printk: clean up
handling of log-levels and newlines") changed printk semantics.  printk
lines with multiple KERN_<level> prefixes are no longer emitted as
before the patch.

<level> is now included in the output on each additional use.

Remove all uses of multiple KERN_<level>s in formats.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

These warnings were observed on MIPS32 using 2.6.31-rc1 and gcc-4.2.0:

mm/page_alloc.c: In function 'alloc_pages_exact':
mm/page_alloc.c:1986: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast

drivers/usb/mon/mon_bin.c: In function 'mon_alloc_buff':
drivers/usb/mon/mon_bin.c:1264: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast

[akpm@linux-foundation.org: fix kernel/perf_counter.c too]
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The sh7724 processor has two on-chip r8a66597 blocks, so add
it to the list of processors for SUPERH_ON_CHIP_R8A66597.
Signed-off-by: NMagnus Damm <damm@igel.co.jp>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

This commit 335f8514 has stopped
properly checking if there is any usb serial associated with the tty in
the close function. It happens the close function is called by releasing
the terminal right after opening the device fails.

As an example, open fails with a non-existing device, when probe has
never been called, because the device has never been plugged. This is
common in systems with static modules and no udev.
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This commit 10077d4a has stopped
checking if there was a valid acm device associated to the tty, which is
not true right after open fails and tty subsystem tries to close the
device.

As an example, open fails with a non-existing device, when probe has
never been called, because the device has never been plugged. This is
common in systems with static modules and no udev.
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is required, otherwise a user will get a EINVAL while opening a
non-existing device, instead of ENODEV.

This is what I get with this patch applied now instead of an "Invalid
argument".

  cascardo@vespa:~$ cat /dev/ttyACM0
  cat: /dev/ttyACM0: No such device
  cascardo@vespa:~$
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While it looks like xhci was written with both PCI and non-PCI in mind,
apparently only the former has seen any testing. xhci-mem.o can be "fixed"
with a linux/dmapool.h include, but there are still parts of the code that
make use of struct pci_dev directly. So, at least more work is needed before
this can be turned on for non-PCI builds:

  CC      drivers/usb/host/xhci-mem.o
drivers/usb/host/xhci-mem.c: In function 'xhci_segment_alloc':
drivers/usb/host/xhci-mem.c:45: error: implicit declaration of function 'dma_pool_alloc'
drivers/usb/host/xhci-mem.c:45: warning: assignment makes pointer from integer without a cast
drivers/usb/host/xhci-mem.c: In function 'xhci_segment_free':
drivers/usb/host/xhci-mem.c:67: error: implicit declaration of function 'dma_pool_free'
drivers/usb/host/xhci-mem.c: In function 'xhci_alloc_virt_device':
drivers/usb/host/xhci-mem.c:239: warning: assignment makes pointer from integer without a cast
drivers/usb/host/xhci-mem.c:248: warning: assignment makes pointer from integer without a cast
drivers/usb/host/xhci-mem.c: In function 'xhci_mem_cleanup':
drivers/usb/host/xhci-mem.c:578: error: implicit declaration of function 'dma_pool_destroy'
drivers/usb/host/xhci-mem.c: In function 'xhci_mem_init':
drivers/usb/host/xhci-mem.c:657: error: implicit declaration of function 'dma_pool_create'
drivers/usb/host/xhci-mem.c:658: warning: assignment makes pointer from integer without a cast
drivers/usb/host/xhci-mem.c:663: warning: assignment makes pointer from integer without a cast
make[3]: *** [drivers/usb/host/xhci-mem.o] Error 1

  CC      drivers/usb/host/xhci-pci.o
drivers/usb/host/xhci-pci.c: In function 'xhci_pci_reinit':
drivers/usb/host/xhci-pci.c:39: error: implicit declaration of function 'pci_set_mwi'
drivers/usb/host/xhci-pci.c: At top level:
drivers/usb/host/xhci-pci.c:151: error: 'usb_hcd_pci_probe' undeclared here (not in a function)
drivers/usb/host/xhci-pci.c:152: error: 'usb_hcd_pci_remove' undeclared here (not in a function)
drivers/usb/host/xhci-pci.c:155: error: 'usb_hcd_pci_shutdown' undeclared here (not in a function)
drivers/usb/host/xhci-pci.c:159: warning: function declaration isn't a prototype
drivers/usb/host/xhci-pci.c:164: warning: function declaration isn't a prototype
make[3]: *** [drivers/usb/host/xhci-pci.o] Error 1

Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add Makefile and Kconfig entries for the xHCI host controller driver.
List Sarah Sharp as the maintainer for the xHCI driver.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Narrow down time spent holding the xHCI spinlock so that it's only used to
protect the xHCI rings, not as mutual exclusion.  Stop allocating memory
while holding the spinlock and calling xhci_alloc_virt_device() and
xhci_endpoint_init().

The USB core should have locking in it to prevent device state to be
manipulated by more than one kernel thread.  E.g. you can't free a device
while you're in the middle of setting a new configuration.  So removing
the locks from the sections where xhci_alloc_dev() and
xhci_reset_bandwidth() touch xHCI's representation of the device should be
OK.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Mask off the lower 16 bits of the interrupt control register, instead of
masking off the upper 16 bits.  The interrupt moderation interval field is
the lower 16 bytes, and is set to 0x4000 (1ms) by default.  The previous
code was adding 40 us to the default value, instead of setting it to 40
us.  This makes performance really bad.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The packed attribute allows gcc to muck with the alignment of data
structures, which may lead to byte-wise writes that break atomicity of
writes.  Packed should only be used when the compile may add undesired
padding to the structure.  Each element of the structure will be aligned
by C based on its size and the size of the elements around it.  E.g. a u64
would be aligned on an 8 byte boundary, the next u32 would be aligned on a
four byte boundary, etc.

Since most of the xHCI structures contain only u32 bit values, removing
the packed attribute for them should be harmless.  (A future patch will
change some of the twin 32-bit address fields to one 64-bit field, but all
those places have an even number of 32-bit fields before them, so the
alignment should be correct.)  Add BUILD_BUG_ON statements to check that
the compiler doesn't add padding to the data structures that have a
hardware-defined layout.

While we're modifying the registers, change the name of intr_reg to
xhci_intr_reg to avoid global conflicts.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Greg KH introduced a bug into xhci_trb_virt_to_dma() when he changed the
type of offset to dma_addr_t from unsigned int and dropped the casts to
unsigned int around the virtual address pointer subtraction.

trb and seg->trbs are both valid pointers to virtual addresses, so the
compiler will mod the subtraction by the size of union trb (16 bytes).
segment_offset is an unsigned long, which is guaranteed to be at least as
big as a void *.

Drop the void * casts in the first if statement because trb and seg->trbs
are both pointers of the same type (pointers to union trb).
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Replace if-elseif-else with switch-case
to keep the code consistent which is semantically same

Switch-case is used here,
http://www.spinics.net/lists/linux-usb/msg17201.html
Making consistent at other places in usb/core

Also easier to read and maintain when USB4.0, 5.0, ... comes
Signed-off-by: NViral Mehta <viral.mehta@einfochips.com>
Tested-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

xhci-mem.c includes calls to dma_pool_alloc() and other functions defined
in linux/dmapool.h.  Make sure to include that header file.
Reported-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Make sure the error path in xhci_urb_enqueue() releases the spinlock
before it returns.  Reported by Oliver in
	http://marc.info/?l=linux-usb&m=124091637311832&w=2Reported-by: NOliver Neukum <oliver@neukum.org>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Differentiate between SuperSpeed endpoint companion descriptor and the
wireless USB endpoint companion descriptor.  Make all structure names for
this descriptor have "ss" (SuperSpeed) in them.  David Vrabel asked for
this change in http://marc.info/?l=linux-usb&m=124091465109367&w=2Reported-by: NDavid Vrabel <david.vrabel@csr.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Force the compiler to write the cycle bit of the Link TRB last.  This
ensures that the hardware doesn't think it owns the Link TRB before we set
the chain bit.  Reported by Oliver in this thread:
	http://marc.info/?l=linux-usb&m=124091532410219&w=2Reported-by: NOliver Neukum <oliver@neukum.org>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Drop spinlock in xhci_irq() error path.
This fixes the issue reported by Oliver Neukum on this thread:
	http://marc.info/?l=linux-usb&m=124090924401444&w=2

Remove unnecessary register read reported by Viral Mehta:
	http://marc.info/?l=linux-usb&m=124091326007398&w=2Reported-by: NOliver Neukum <oliver@neukum.org>
Reported-by: NViral Mehta <viral.mehta@einfochips.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Make all globally visible functions start with xhci_ and mark functions as
static if they're only called within the same C file.  Fix some long lines
while we're at it.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Make sure to preserve all bits *except* the TRB_CHAIN bit when giving a
Link TRB to the hardware.  We need to save things like TRB type and the
toggle bit in the control dword.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The 0.95 xHCI spec says that if the xHCI HW support 64-bit addressing, you
must write the whole 64-bit address as one atomic operation, or write the
low 32 bits, and then the high 32 bits.  I had the register writes
swapped in some places.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This fixes the warning:
drivers/usb/host/xhci.h:1083: warning: passing argument 1 of ‘xhci_to_hcd’ discards qualifiers from pointer target type
drivers/usb/host/xhci.h:1083: warning: passing argument 1 of ‘xhci_to_hcd’ discards qualifiers from pointer target type
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Turns out someone never built this code on a 64bit platform.

Someone owes me a beer...
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The former is way to generic for a global symbol.

Fixes this build error:

drivers/usb/built-in.o: In function `.handle_event': (.text+0x67dd0): multiple definition of `.handle_event'
drivers/pcmcia/built-in.o:(.text+0xcfcc): first defined here
drivers/usb/built-in.o: In function `handle_event': (.opd+0x5bc8): multiple definition of `handle_event'
drivers/pcmcia/built-in.o:(.opd+0xed0): first defined here
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add URB cancellation support to the xHCI host controller driver.  This
currently supports cancellation for endpoints that do not have streams
enabled.

An URB is represented by a number of Transaction Request Buffers (TRBs),
that are chained together to make one (or more) Transaction Descriptors
(TDs) on an endpoint ring.  The ring is comprised of contiguous segments,
linked together with Link TRBs (which may or may not be chained into a TD).

To cancel an URB, we must stop the endpoint ring, make the hardware skip
over the TDs in the URB (either by turning them into No-op TDs, or by
moving the hardware's ring dequeue pointer past the last TRB in the last
TD), and then restart the ring.

There are times when we must drop the xHCI lock during this process, like
when we need to complete cancelled URBs.  We must ensure that additional
URBs can be marked as cancelled, and that new URBs can be enqueued (since
the URB completion handlers can do either).  The new endpoint ring
variables cancels_pending and state (which can only be modified while
holding the xHCI lock) ensure that future cancellation and enqueueing do
not interrupt any pending cancellation code.

To facilitate cancellation, we must keep track of the starting ring
segment, first TRB, and last TRB for each URB.  We also need to keep track
of the list of TDs that have been marked as cancelled, separate from the
list of TDs that are queued for this endpoint.  The new variables and
cancellation list are stored in the xhci_td structure.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add support for bulk URBs that pass scatter gather lists to xHCI.  This allows
xHCI to more efficiently enqueue these transfers, and allows the host
controller to take advantage of USB 3.0 "bursts" for bulk endpoints.

Use requested length to calculate the number of TRBs needed for a scatter gather
list transfer, instead of using the number of sglist entries.  The application
can pass down a scatter gather list that is bigger than it needs for the
requested transfer.

Scatter gather entries can cross 64KB boundaries, so be careful to setup TRBs
such that no buffer crosses a 64KB boundary.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This is the original patch I created before David Vrabel posted a better
patch (http://marc.info/?l=linux-usb&m=123377477209109&w=2) that does
basically the same thing.  This patch will get replaced with his
(modified) patch later.

Allow USB device drivers that use usb_sg_init() and usb_sg_wait() to push
bulk endpoint scatter gather lists down to the host controller drivers.
This allows host controller drivers to more efficiently enqueue these
transfers, and allows the xHCI host controller to better take advantage of
USB 3.0 "bursts" for bulk endpoints.

This patch currently only enables scatter gather lists for bulk endpoints.
Other endpoint types that use the usb_sg_* functions will not have their
scatter gather lists pushed down to the host controller.  For periodic
endpoints, we want each scatterlist entry to be a separate transfer.
Eventually, HCDs could parse these scatter-gather lists for periodic
endpoints also.  For now, we use the old code and call usb_submit_urb()
for each scatterlist entry.

The caller of usb_sg_init() can request that all bytes in the scatter
gather list be transferred by passing in a length of zero.  Handle that
request for a bulk endpoint under xHCI by walking the scatter gather list
and calculating the length.  We could let the HCD handle a zero length in
this case, but I'm not sure if the core layers in between will get
confused by this.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Allow device drivers to submit URBs to bulk endpoints on devices under an
xHCI host controller.  Share code between the control and bulk enqueueing
functions when it makes sense.

To get the best performance out of bulk transfers, SuperSpeed devices must
have the bMaxBurst size copied from their endpoint companion controller
into the xHCI device context.  This allows the host controller to "burst"
up to 16 packets before it has to wait for the device to acknowledge the
first packet.

The buffers in Transfer Request Blocks (TRBs) can cross page boundaries,
but they cannot cross 64KB boundaries.  The buffer must be broken into
multiple TRBs if a 64KB boundary is crossed.

The sum of buffer lengths in all the TRBs in a Transfer Descriptor (TD)
cannot exceed 64MB.  To work around this, the enqueueing code must enqueue
multiple TDs.  The transfer event handler may incorrectly give back the
URB in this case, if it gets a transfer event that points somewhere in the
first TD.  FIXME later.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Since the xHCI host controller hardware (xHC) has an internal schedule, it
needs a better representation of what devices are consuming bandwidth on
the bus.  Each device is represented by a device context, with data about
the device, endpoints, and pointers to each endpoint ring.

We need to update the endpoint information for a device context before a
new configuration or alternate interface setting is selected.  We setup an
input device context with modified endpoint information and newly
allocated endpoint rings, and then submit a Configure Endpoint Command to
the hardware.

The host controller can reject the new configuration if it exceeds the bus
bandwidth, or the host controller doesn't have enough internal resources
for the configuration.  If the command fails, we still have the older
device context with the previous configuration.  If the command succeeds,
we free the old endpoint rings.

The root hub isn't a real device, so always say yes to any bandwidth
changes for it.

The USB core will enable, disable, and then enable endpoint 0 several
times during the initialization sequence.  The device will always have an
endpoint ring for endpoint 0 and bandwidth allocated for that, unless the
device is disconnected or gets a SetAddress 0 request.  So we don't pay
attention for when xhci_check_bandwidth() is called for a re-add of
endpoint 0.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Originally, the USB core had no support for allocating bandwidth when a
particular configuration or alternate setting for an interface was
selected.  Instead, the device driver's URB submission would fail if
there was not enough bandwidth for a periodic endpoint.  Drivers could
work around this, by using the scatter-gather list API to guarantee
bandwidth.

This patch adds host controller API to allow the USB core to allocate or
deallocate bandwidth for an endpoint.  Endpoints are added to or dropped
from a copy of the current schedule by calling add_endpoint() or
drop_endpoint(), and then the schedule is atomically evaluated with a
call to check_bandwidth().  This allows all the endpoints for a new
configuration or alternate setting to be added at the same time that the
endpoints from the old configuration or alt setting are dropped.

Endpoints must be added to the schedule before any URBs are submitted to
them.  The HCD must be allowed to reject a new configuration or alt
setting before the control transfer is sent to the device requesting the
change.  It may reject the change because there is not enough bandwidth,
not enough internal resources (such as memory on an embedded host
controller), or perhaps even for security reasons in a virtualized
environment.

If the call to check_bandwidth() fails, the USB core must call
reset_bandwidth().  This causes the schedule to be reverted back to the
state it was in just after the last successful check_bandwidth() call.

If the call succeeds, the host controller driver (and hardware) will have
changed its internal state to match the new configuration or alternate
setting.  The USB core can then issue a control transfer to the device to
change the configuration or alt setting.  This allows the core to test new
configurations or alternate settings before unbinding drivers bound to
interfaces in the old configuration.

WIP:

The USB core must add endpoints from all interfaces in a configuration
to the schedule, because a driver may claim that interface at any time.
A slight optimization might be to add the endpoints to the schedule once
a driver claims that interface.  FIXME

This patch does not cover changing alternate settings, but it does
handle a configuration change or de-configuration.  FIXME

The code for managing the schedule is currently HCD specific.  A generic
scheduling algorithm could be added for host controllers without
built-in scheduling support.  For now, if a host controller does not
define the check_bandwidth() function, the call to
usb_hcd_check_bandwidth() will always succeed.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>