This patch (as937) fixes a minor bug in the autosuspend usage-counting
code. Each hub's usage counter keeps track of the number of
unsuspended children. However the current driver increments the
counter after registering a new child, by which time the child may
already have been suspended and caused the counter to go negative.
The obvious solution is to increment the counter before registering
the child.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves. This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.
It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.
The patch causes all kernel threads to be nonfreezable by default (ie. to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE. It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear. Additionally, it updates documentation to
describe the freezing of tasks more accurately.
[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch (as920) adds an extra level of protection to the
USB-Persist facility. Now it will apply by default only to hubs; for
all other devices the user must enable it explicitly by setting the
power/persist device attribute.
The disconnect_all_children() routine in hub.c has been removed and
its code placed inline. This is the way it was originally as part of
hub_pre_reset(); the revised usage in hub_reset_resume() is
sufficiently different that the code can no longer be shared.
Likewise, mark_children_for_reset() is now inline as part of
hub_reset_resume(). The end result looks much cleaner than before.
The sysfs interface is updated to add the new attribute file, and
there are corresponding documentation updates.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as919) unifies the code paths used for normal resume and
for reset-resume. Earlier I had failed to note a section in the USB
spec which requires the host to resume a suspended port before
resetting it if the attached device is enabled for remote wakeup.
Since the port has to be resumed anyway, we might as well reuse the
existing code.
The main changes are:
usb_reset_suspended_device() is eliminated.
usb_root_hub_lost_power() is moved down next to the
hub_reset_resume() routine, to which it is logically
related.
finish_port_resume() does a port reset() if the device's
reset_resume flag is set.
usb_port_resume() doesn't check whether the port is initially
enabled if this is a USB-Persist sort of resume.
Code to perform the port reset is added to the resume pathway
for the non-CONFIG_USB_SUSPEND case.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as918) introduces a new USB driver method: reset_resume.
It is called when a device needs to be reset as part of a resume
procedure (whether because of a device quirk or because of the
USB-Persist facility), thereby taking over a role formerly assigned to
the post_reset method. As a consequence, post_reset no longer needs
an argument indicating whether it is being called as part of a
reset-resume. This separation of functions makes the code clearer.
In addition, the pre_reset and post_reset method return types are
changed; they now must return an error code. The return value is
unused at present, but at some later time we may unbind drivers and
re-probe if they encounter an error during reset handling.
The existing pre_reset and post_reset methods in the usbhid,
usb-storage, and hub drivers are updated to match the new
requirements. For usbhid the post_reset routine is also used for
reset_resume (duplicate method pointers); for the other drivers a new
reset_resume routine is added. The change to hub.c looks bigger than
it really is, because mark_children_for_reset_resume() gets moved down
next to the new hub_reset_resume() routine.
A minor change to usb-storage makes the usb_stor_report_bus_reset()
routine acquire the host lock instead of requiring the caller to hold
it already.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as917) removes a now-unnecessary level of subroutine
nesting from hub.c. Since usb_port_suspend() does nothing but call
hub_port_suspend(), and usb_port_resume() does nothing but call
hub_port_resume(), there's no reason to keep the routines separate.
Also included in the patch are a few cosmetic changes involving
whitespace and use of braces.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as916) completes the separation of code paths for suspend
and resume of root hubs as opposed to non-root devices. Root hubs
will be power-managed through their bus_suspend and bus_resume
methods, whereas normal devices will use usb_port_suspend() and
usb_port_resume().
Changes to the hcd_bus_{suspend,resume} routines mostly represent
motion of code that was already present elsewhere. They include:
Adding debugging log messages,
Setting the device state appropriately, and
Adding a resume recovery time delay.
Changes to the port-suspend and port-resume routines in hub.c include:
Removal of checks for root devices (since they will never
be triggered), and
Removal of checks for NULL or invalid device pointers (these
were left over from earlier kernel versions and aren't needed
at all).
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as915b) combines the public routine usb_port_suspend() and
the private routine __usb_port_suspend() into a single function.
By removing the explicit mention of otg_port in the call to
__usb_port_suspend(), we prevent a possible error in which the system
tries to perform HNP on the wrong port when a non-targeted device is
plugged into a non-OTG port.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Patch is to prevent the OTG host of doing 3 times enumeration of
device when the Host suspends for HNP. The error code used in
this case is ENOTSUPP.
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Okay, found it. The root cause here was a missing CONFIG_USB_SUSPEND=y,
which means the hci_usb device never got marked as USB_STATE_SUSPENDED,
which then caused the loop to go on forever.
The system works fine now with CONFIG_USB_SUSPEND=y in the .config.
Here's the patch to prevent future lockups for this or other causes.
I no longer need it, but it does still seem a good idea.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as898) changes the port reset code in the hub driver. If
a connect change occurs, it is reported the same way as a disconnect
(which of course is what it really is).
It also changes usb_reset_device(), to prevent the routine from futilely
retrying the reset after a disconnect has occurred.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as888) adds a new USB device quirk for devices which are
unable to resume correctly. By using the new code added for the
USB-persist facility, it is a simple matter to reset these devices
instead of resuming them. To get things kicked off, a quirk entry is
added for the Philips PSC805.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as886) adds the controversial USB-persist facility,
allowing USB devices to persist across a power loss during system
suspend.
The facility is controlled by a new Kconfig option (with appropriate
warnings about the potential dangers); when the option is off the
behavior will remain the same as it is now. But when the option is
on, people will be able to use suspend-to-disk and keep their USB
filesystems intact -- something particularly valuable for small
machines where the root filesystem is on a USB device!
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This revised patch (as893c) improves the method used by the hub driver
to release its private data structure. The current code is non-robust,
relying on a memory region not getting reused by another driver after
it has been freed. The patch adds a reference count to the structure,
resolving the question of when to release it.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as892) removes the "locktree" routine from the hub driver.
It currently is used in only one place, by a single kernel thread;
hence it isn't doing any good.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as889) prevents the hub driver from trying to resume a
port when there is a new connection. For one thing, the resume is not
needed -- the upcoming port reset will clear the suspend feature
automatically. For another, on some systems the resume fails and
causes problems.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as885) moves the root-hub bus_suspend() and bus_resume()
method calls from the hub driver's suspend and resume methods into the
usb_generic driver methods, where they make just as much sense.
Their old locations were not fully correct. For example, in a kernel
compiled without CONFIG_USB_SUSPEND, if one were to do:
echo -n 1-0:1.0 >/sys/bus/usb/drivers/hub/unbind
to unbind the hub driver from a root hub, there would then be no way
to suspend that root hub. Attempts to put the system to sleep would
fail; the USB controller driver would refuse to suspend because the
root hub was still active.
The patch also makes a very slight change in the way devices with no
driver are handled during suspend. Rather than doing a standard USB
port-suspend directly, now the suspend routine in usb_generic is
called. In practice this should never affect anyone.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The prev_state member of struct dev_pm_info (defined in include/linux/pm.h) is
only used during a resume to check if the device's state before the suspend was
'off', in which case the device is not resumed. However, in such cases the
decision whether or not to resume the device should be made on the driver level
and the resume callbacks from the device's bus and class should be executed
anyway (the may be needed for some things other than just powering on the
device).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 <stern@rowland.harvard.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg KH <gregkh@suse.de>
Cc: Mark Lord <lkml@rtr.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch (as910) fixes a ratelimit modification so that the
original error-handling path will be followed even when the log-rate
limitation kicks in.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as905) removes a micro-optimization from the hub port
initialization code. Previously we had been using a short timeout on
the first attempt the read the device descriptor; now we will use the
standard timeout length.
It's not clear that the short timeout ever provided any benefit. And
now we know of one case where it actually hurts: The device can't meet
the short timeout and then it gets terminally confused.
This fixes Bugzilla #8444.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
o The "real" usb-devices export now a device node which can
populate /dev/bus/usb.
o The usb_device class is optional now and can be disabled in the
kernel config. Major/minor of the "real" devices and class devices
are the same.
o The environment of the usb-device event contains DEVNUM and BUSNUM to
help udev and get rid of the ugly udev rule we need for the class
devices.
o The usb-devices and usb-interfaces share the same bus, so I used
the new "struct device_type" to let these devices identify
themselves. This also removes the current logic of using a magic
platform-pointer.
The name of the device_type is also added to the environment
which makes it easier to distinguish the different kinds of devices
on the same subsystem.
It looks like this:
add@/devices/pci0000:00/0000:00:1d.1/usb2/2-1
ACTION=add
DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/2-1
SUBSYSTEM=usb
SEQNUM=1533
MAJOR=189
MINOR=131
DEVTYPE=usb_device
PRODUCT=46d/c03e/2000
TYPE=0/0/0
BUSNUM=002
DEVNUM=004
This udev rule works as a replacement for usb_device class devices:
SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \
NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644"
Updated patch, which needs the device_type patches in Greg's tree.
I also got a bugzilla assigned for this. :)
https://bugzilla.novell.com/show_bug.cgi?id=250659
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Duplicate what Zach Brown did for pr_debug in commit
8b2a1fd1b3
[akpm@linux-foundation.org: fix a couple of things which broke]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
flaky hardware can cause a lot of debounce failed messages. To limit
the performance impact, a ratelimit should be used.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This adds a blacklist to the USB core to handle some autosuspend and
string issues that devices have.
Originally written by Oliver, but hacked up a lot by Greg.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as849) fixes a bug in the USB hub driver. A single
pre-allocated buffer is used for all port status reads, but nothing
guarantees exclusive use of the buffer. A mutex is added to provide
this guarantee.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as847) makes some small changes to the hub driver's
suspend method:
For root hubs, the status URB should be unlinked and other
activity stopped _before_ the bus_suspend method is called.
The test for hdev->bus being NULL has been removed, since
it can never succeed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The whole approach is simply wrong. Forking a thread means that
- errors are ignored
- locking is ignored
Doing this correctly would require major surgery for questionable benefit.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Disable the USB_MULTITHREAD_PROBE option because it causes crashes on
people's machines and they never remember to actually read the config
help files.
No one likes this, everyone hates it, I'm going to go eat worms...
The full logic will be ripped out later.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move process freezing functions from include/linux/sched.h to freezer.h, so
that modifications to the freezer or the kernel configuration don't require
recompiling just about everything.
[akpm@osdl.org: fix ueagle driver]
Signed-off-by: Nigel Cunningham <nigel@suspend2.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SLAB_KERNEL is an alias of GFP_KERNEL.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SLAB_ATOMIC is an alias of GFP_ATOMIC
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix up arch-specific work items where possible to use the new work_struct and
delayed_work structs.
Three places that enqueue bits of their stack and then return have been marked
with #error as this is not permitted.
Signed-Off-By: David Howells <dhowells@redhat.com>
Thanks to several earlier patches, usb_autosuspend_device() and
usb_autoresume_device() are never called with a second argument other
than 1. This patch (as819) removes the now-redundant argument.
It also consolidates some common code between those two routines,
putting it into a new subroutine called usb_autopm_do_device(). And
it includes a sizable kerneldoc update for the affected functions.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as818b) simplifies autosuspend processing by keeping track
of the number of unsuspended children of each USB hub. This will
permit us to avoid a good deal of unnecessary work all the time; we
will no longer have to create a bunch of workqueue entries to carry
out autosuspend requests, only to have them fail because one of the
hub's children isn't suspended.
The basic idea is simple. There already is a usage counter in the
usb_device structure for preventing autosuspends. The patch just
increments that counter for every unsuspended child. There's only one
tricky part: When a device disconnects we need to remember whether it
was suspended at the time (leave the counter alone) or not (decrement
the counter).
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as817) simplifies the remote-wakeup processing in the hub
driver. Now instead of using a specialized code path, it relies on
the standard USB resume routines. The hub_port_resume() function does
an initial get_port_status() to see whether the port has already
resumed itself (as it does when a remote-wakeup request is sent).
This will slow down handling of other resume events slightly, but not
enough to matter.
The patch also changes the hub_port_status() routine, making it return
an error if a short reply is received.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as742b) adds autosuspend/autoresume support to the USB hub
driver. The largest aspect of the change is that we no longer need a
special flag for root hubs that want to be resumed. Now every hub is
autoresumed whenever khubd needs to access it.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Might speed up some systems. If nothing else, a bad driver should not
take the whole USB subsystem down with it.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as809b) moves the declaration of the hub driver's private
data structure from hub.h into the hub.c source file. Lots of other
files import hub.h; they have no need to know about the details of the
hub driver's private data.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 <inaky.perez-gonzalez@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove complaint from newer GCCs; they don't like forward function
declarations except in top-level contexts.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
This patch (as791b) fixes things up to avoid compiler warnings or
errors when CONFIG_USB_SUSPEND or CONFIG_PM isn't set.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Somewhere along the line, a variable in a USB-OTG codepath
stopped being used; this removes the relevant compiler warning.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch(as785) forces the PM core to resume a root hub after a
power loss during system sleep. If the root hub had been suspended
before the system sleep then normally the PM core would not resume it
afterward. Without this resume, various sorts of wakeup events (like
port change events) can get lost.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Alan Stern