Accroding commit 0994375e, which is adding remove_id sysfs attr
for pci drivers, for management tools dynamically bind/unbind
a pci/usb devices to a specified drivers; with this patch,
the management tools can be simplied.
And the original code didn't handle the failure of
usb_create_newid_file, fixed in this patch.
Signed-off-by: CHENG Renquan <rqcheng@smu.edu.sg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1303) revises the USB Power Management infrastructure to
make it compatible with the new driver-model Runtime PM framework:
Drivers are no longer allowed to access intf->pm_usage_cnt
directly; the PM framework manages its own usage counters.
usb_autopm_set_interface() is eliminated, because it directly
sets intf->pm_usage_cnt.
usb_autopm_enable() and usb_autopm_disable() are eliminated,
because they call usb_autopm_set_interface().
usb_autopm_get_interface_no_resume() and
usb_autopm_put_interface_no_suspend() are added. They
correspond to pm_runtime_get_noresume() and
pm_runtime_put_noidle() in the PM framework.
The power/level attribute no longer accepts "suspend", only
"on" and "auto". The PM framework doesn't allow devices to be
forced into a suspended mode.
The hub driver contains the only code that violates the new
guidelines. It is updated to use the new interface routines instead.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This is not exported from the usb core, yet we rely on it to create
paths to interfaces for this device in sysfs. Export it to make
userspace tools have an easier time to figure things out.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a missing goto. We dereference usb_class on the next line.
Found by smatch static checker.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1302) removes the auto_pm flag from struct usb_device.
The flag's only purpose was to distinguish between autosuspends and
external suspends, but that information is now available in the
pm_message_t argument passed to suspend methods.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Quiet the following sparse noise:
warning: Using plain integer as NULL pointer
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
USB drivers that create character devices call usb_register_dev in their
probe function. This associates the usb_interface device with that minor
number and creates the character device and announces it to the world.
However, the driver's probe function is called before the new
usb_interface is added to the driver's klist_devices.
This is a problem because userspace will respond to the character device
creation announcement by opening the character device. The driver's open
function will the call usb_find_interface to find the usb_interface
associated with that minor number. usb_find_interface will walk the
driver's list of devices and find the usb_interface with the matching
minor number.
Because the announcement happens before the usb_interface is added to the
driver's klist_devices, a race condition exists. A straightforward fix
is to walk the list of devices on usb_bus_type instead since the device
is added to that list before the announcement occurs.
bus_find_device calls get_device to bump the reference count on the found
device. It is arguable that the reference count should be dropped by the
caller of usb_find_interface instead of usb_find_interface, however,
the current users of usb_find_interface do not expect this.
Signed-off-by: Russ Dill <Russ.Dill@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In map_urb_for_dma(), the DMA address returned by dma_map_single()
is not checked to determine if it is legal. This lack of checking
contributed to a problem with the libertas wireless driver
(http://marc.info/?l=linux-wireless&m=125695331205062&w=2). The
difficulty was not detected until the buffer was unmapped. By this time
memory corruption had occurred.
The situation is fixed by testing the returned DMA address, and
returning -EAGAIN if the address is invalid.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1298) fixes a bug in the new scatter-gather URB
facility. If an URB uses a scatterlist then it should not have the
URB_NO_INTERRUPT flag set; otherwise the system won't be notified when
the transfer completes.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Vrabel <david.vrabel@csr.com>
CC: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1297) adds a "remove" attribute to each USB device's
directory in sysfs. Writing to this attribute causes the device to be
deconfigured (the same as writing 0 to the "bConfigurationValue"
attribute) and then tells the hub driver to disable the device's
upstream port. The device remains locked during these activities so
there is no possibility of it getting reconfigured in between. The
port will remain disabled until after the device is unplugged.
The purpose of this is to provide a means for user programs to imitate
the "Safely remove hardware" applet in Windows. Some devices do
expect their ports to be disabled before they are unplugged, and they
provide visual feedback to users indicating when they can safely be
unplugged.
The security implications are minimal. Writing to the "remove"
attribute is no more dangerous than writing to the
"bConfigurationValue" attribute.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: David Zeuthen <davidz@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1296) gets rid of the fixed DMA-buffer mapping used by
the hub driver for its status URB. This URB doesn't get used much --
mainly when a device is plugged in or unplugged -- so the dynamic
mapping overhead is minimal. And most systems have many fewer
external hubs than root hubs, which don't need a mapped buffer anyway.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb: better error handling in usb_port_suspend
- disable remote wakeup only if it was enabled
- refuse to autosuspend if remote wakeup fails to be enabled
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Check urb->interval on interrupt transfers and allow those with valid
values (6 <= interval <= 16).
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The WHCI HCD will also support urbs with scatter-gather lists. Add a
usb_bus field to indicated how many sg list elements are supported by
the HCD. Use this to decide whether to pass the scatter-list to the HCD
or not.
Make the usb-storage driver use this new field.
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Knowing which configuration was chosen is a debugging aid more than it
is informational.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1304) fixes a regression in ehci-hcd. Evidently some
hubs don't handle Clear-TT-Buffer requests correctly, so we should
avoid sending them when they don't appear to be absolutely necessary.
The reported symptom is that output on a downstream audio device cuts
out because the hub stops relaying isochronous packets.
The patch prevents Clear-TT-Buffer requests from being sent following
a STALL handshake. In theory a STALL indicates either that the
downstream device sent a STALL or that no matching TT buffer could be
found. In either case, the transfer is completed and the TT buffer
does not remain busy, so it doesn't need to be cleared.
Also, the patch fixes a minor flaw in the code that actually sends the
Clear-TT-Buffer requests. Although the pipe direction isn't really
used for control transfers, it should be a Send rather than a Receive.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Javier Kohen <jkohen@users.sourceforge.net>
CC: David Brownell <david-b@pacbell.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a hook for updating xHCI internal structures after khubd fetches the
hub descriptor and sets up the hub's TT information. The xHCI driver must
update the internal structures before devices under the hub can be
enumerated.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The xHCI driver needs to set the route string in the slot context of all
devices, not just SuperSpeed devices. The route string concept was added
in the USB 3.0 specification, section 10.1.3.2. Each hub in the topology
is expected to have no more than 15 ports in order for the route string of
a device to be unique. SuperSpeed hubs are restricted to only having 15
ports, but FS/LS/HS hubs are not. The xHCI specification says that if the
port number the device is under is greater than 15, that portion of the
route string shall be set to 15.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb: check for IO errors usb_set_interface can return
if they happen while unbinding a flag is set to retry upon probe
if they happen during probe they are handled as probe errors
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1283) adds a new flag, USBDEVFS_URB_BULK_CONTINUATION,
to usbfs. It is intended for userspace libraries such as libusb and
openusb. When they have to break up a single usbfs bulk transfer into
multiple URBs, they will set the flag on all but the first URB of the
series.
If an error other than an unlink occurs, the kernel will automatically
cancel all the following URBs for the same endpoint and refuse to
accept new submissions, until an URB is encountered that is not marked
as a BULK_CONTINUATION. Such an URB would indicate the start of a new
transfer or the presence of an older library, so the kernel returns to
normal operation.
This enables libraries to delimit bulk transfers correctly, even in
the presence of early termination as indicated by short packets.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The previous code had a bug that would add a trailing null byte to
the returned descriptor.
Signed-off-by: George Spelvin <linux@horizon.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb_buffer_map_sg should return negative on error according to
its documentation. But dma_map_sg returns 0 on error. Take this
into account and return -ENOMEM in such situation.
While at it, return -EINVAL instead of -1 when wrong input is
passed in.
If this wasn't done, usb_sg_* operations used after usb_sg_init
which returned 0 may cause oopses/deadlocks since we don't init
structures/entries, esp. completion and status entry.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The current limit only allows isochronous transfers up to 32kbyte/urb,
updating this to 192 kbyte/urb improves the reliability of the
transfer. USB 2.0 transfer is possible with 32kbyte but increases the
chance of corrupted/incomplete data when the system is performing some
other tasks in the background.
http://www.spinics.net/lists/linux-usb/msg19955.html
Signed-off-by: Markus Rechberger <mrechberger@gmail.com>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1268) changes the way usbcore handles child devices that
undergo a disconnection and reconnection while the parent hub is
suspended. Currently, if the child isn't enabled for remote wakeup we
leave it alone, figuring that it will go through a reset-resume when
somebody tries to use it.
However this isn't a good approach if the reason for the disconnection
is that the child decided to switch modes or in some other way alter
its descriptors. In that case we want to re-enumerate it as soon as
possible, not wait until somebody forces a reset-resume.
To resolve the issue, this patch treats reconnected suspended child
devices as though they had requested a remote wakeup, even if they
weren't enabled for it. The mode switch or descriptor change will be
detected during the reset part of the reset-resume, and the device
will be re-enumerated immediately.
The disadvantage of this change is that it will cause autosuspended
devices to be resumed when the computer wakes up from a system sleep
during which the root hub was reset or lost power. This shouldn't
matter much; some people would even argue that autosuspended devices
should _always_ be resumed when the system wakes up!
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: "Yang Fei-AFY095" <fei.yang@motorola.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1267) changes usb_kick_khubd() and hdev_to_hub() to make
them more resilient against situations where a hub device isn't bound
to the hub driver. The code assumes that if a root hub was
successfully registered then it must be bound to the hub driver.
But this assumption can fail if the user manually unbinds the hub
driver, or more importantly, if the host controller dies causing
usb_set_configuration to fail.
To protect against these possibilities, make hdev_to_hub() check that
the hub device is configured before dereferencing the active
configuration, and make usb_kick_khubd() check that the pointer to the
hub's private data structure isn't NULL.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1261) reduces the amount of detailed URB information
logged by usbfs when the usbfs_snoop parameter is enabled.
Currently we don't display the final status value for a completed URB.
But we do display the entire data buffer twice: both before submission
and after completion. The after-completion display doesn't limit
itself to the actual_length value. But since usbmon is readily
available in virtually all distributions, there's no reason for usbfs
to print out any buffer contents at all!
So this patch restricts the information to: userspace buffer pointer,
endpoint number, type, and direction, length or actual_length, and
timeout value or status. Now everything fits neatly into a single
line.
Along with those changes, the patch also fixes the snoop output for
the REAPURBNDELAY and REAPURBNDELAY32 ioctls. The current version
omits the 'N' from the names.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1260) changes the pm_usage_cnt field in struct
usb_interface from an int to an atomic_t. This is so that drivers can
invoke the usb_autopm_get_interface_async() and
usb_autopm_put_interface_async() routines without locking and without
fear of corrupting the pm_usage_cnt value.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1258) implements a feature that users have been asking
for: It gives programs the ability to "claim" a port on a hub, via a
new usbfs ioctl. A device plugged into a "claimed" port will not be
touched by the kernel beyond the immediate necessities of
initialization and enumeration.
In particular, when a device is plugged into a "claimed" port, the
kernel will not select and install a configuration. And when a config
is installed by usbfs or sysfs, the kernel will not probe any drivers
for any of the interfaces. (However the kernel will fetch various
string descriptors during enumeration. One could argue that this
isn't really necessary, but the strings are exported in sysfs.)
The patch does not guarantee exclusive access to these devices; it is
still possible for more than one program to open the device file
concurrently. Programs are responsible for coordinating access among
themselves.
A demonstration program showing how to use the new interface can be
found in an attachment to
http://marc.info/?l=linux-usb&m=124345857431452&w=2
The patch also makes a small simplification to the hub driver,
replacing a bunch of more-or-less useless variants of "out of memory"
with a single message.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This fix permits the "new" usbmon to access usb-storage's data buffer
without DMA remapping tricks. It should be compatible with PIO controllers
and not add any new crashes. Note that from now on PIO controllers and
usbmon are uniform in their access pattern and if one crashes then
the other will too. Hopefuly neither does.
As a side effect, we get rid for #ifdefs, which were a little ugly.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When there's a descriptor after the SuperSpeed endpoint companion
descriptor, the previous code would have skipped over twice the length it
was supposed to. This code fixes crashes seen with UASP devices (which
have a UASP descriptor after the SS endpoint companion descriptor).
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>
This allows subsytems to provide devtmpfs with non-default permissions
for the device node. Instead of the default mode of 0600, null, zero,
random, urandom, full, tty, ptmx now have a mode of 0666, which allows
non-privileged processes to access standard device nodes in case no
other userspace process applies the expected permissions.
This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Let attribute group vectors be declared "const". We'd
like to let most attribute metadata live in read-only
sections... this is a start.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1272) changes the error code returned when an open call
for a USB device node fails to locate the corresponding device. The
appropriate error code is -ENODEV, not -ENOENT.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
access_ok() checks must be done on every part of the userspace structure
that is accessed. If access_ok() on one part of the struct succeeded, it
does not imply it will succeed on other parts of the struct. (Does
depend on the architecture implementation of access_ok()).
This changes the __get_user() users to first check access_ok() on the
data structure.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: stable <stable@kernel.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb_parse_ss_endpoint_companion() was supposed to allocate a structure to
hold the SuperSpeed Endpoint Companion descriptor, and either copy the
values the device returned, or fill in default values if the device
descriptor did not include the companion descriptor.
However, the previous code would miss the last endpoint in a configuration
with no descriptors after it. Make usb_parse_endpoint() allocate the SS
endpoint companion descriptor and fill it with default values, even if
we've run out of buffer space in this configuration descriptor.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1262) fixes a bug in usbfs: It refuses to accept
zero-length transfers, and it insists that the buffer pointer be valid
even if there is no data being transferred.
The patch also consolidates a bunch of repetitive access_ok() checks
into a single check, which incidentally fixes the lack of such a check
for Isochronous URBs.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit b7af0bb ("USB: allow malformed LANGID descriptors") broke support
for devices without string descriptor support.
Reporting string descriptors is optional to USB devices, and a device
lets us know it can't deal with strings by responding to the LANGID
request with a STALL token.
The kernel handled that correctly before b7af0bb came in, but failed
hard if the LANGID was reported but broken. More than that, if a device
was not able to provide string descriptors, the LANGID was retrieved
over and over again at each string read request.
This patch changes the behaviour so that
a) the LANGID is only queried once
b) devices which can't handle string requests are not asked again
c) devices with malformed LANGID values have a sane fallback to 0x0409
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts commit cc71329b3b, so that
Red Hat machines can boot properly. It seems that the Red Hat initrd
code tries to watch the /proc/bus/usb/devices file to monitor usb
devices showing up. While this task is prone to lots of races and does
not show the true state of the system, they seem to like it.
So for now, don't move this option under the EMBEDDED config option.
Cc: Scott James Remnant <scott@canonical.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Jeff Chua <jeff.chua.linux@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Added descriptions (for WIRELESS_CONTROLLER and MISC) were taken from
the usb-devices script now included in usbutils.
Also sort the classes in the same order as in include/linux/usb/ch9.h
for easier comparison for future updates.
Signed-off-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixes a memory leak in devio.c::processcompl
If writing to user space fails the packet must be discarded, as it
already has been removed from the queue of completed packets.
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1255) updates the interface for calling
usb_hub_clear_tt_buffer(). Even the name of the function is changed!
When an async URB (i.e., Control or Bulk) going through a high-speed
hub to a non-high-speed device is cancelled or fails, the hub's
Transaction Translator buffer may be left busy still trying to
complete the transaction. The buffer has to be cleared; that's what
usb_hub_clear_tt_buffer() does.
It isn't safe to send any more URBs to the same endpoint until the TT
buffer is fully clear. Therefore the HCD needs to be told when the
Clear-TT-Buffer request has finished. This patch adds a callback
method to struct hc_driver for that purpose, and makes the hub driver
invoke the callback at the proper time.
The patch also changes a couple of names; "hub_tt_kevent" and
"tt.kevent" now look rather antiquated.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit 5fd29d6ccb ("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: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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: Viral Mehta <viral.mehta@einfochips.com>
Tested-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg 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=2
Reported-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg 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: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
