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  1. 04 11月, 2006 1 次提交
  3. 05 10月, 2006 1 次提交
    • D
      IRQ: Maintain regs pointer globally rather than passing to IRQ handlers · 7d12e780
      由 David Howells 提交于 
      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: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
      7d12e780
  5. 29 9月, 2006 1 次提交
  7. 28 9月, 2006 18 次提交
  9. 13 7月, 2006 2 次提交
  11. 01 7月, 2006 1 次提交
  13. 22 6月, 2006 5 次提交
  15. 09 5月, 2006 1 次提交
    • A
      [PATCH] USB: usbcore: don't check the device's power source · 436f5762
      由 Alan Stern 提交于 
      The choose_configuration() routine contains code the determine the
device's power source, so that configurations requiring external power
can be ruled out if the device is running on bus power.  Unfortunately
it turns out that some devices have errors in their config descriptors
and other devices don't like the GET_DEVICE_STATUS request.

Since that information wasn't used for anything else, this patch (as673)
removes the code, leaving only a comment.  It fixes bugzilla entry
#6448.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      436f5762
  17. 15 4月, 2006 2 次提交
  19. 21 3月, 2006 4 次提交
  21. 05 1月, 2006 4 次提交
    • A
      [PATCH] USB: Don't assume root-hub resume succeeds · 2425e9fe
      由 Alan Stern 提交于 
      This patch (as614) makes a small change to the part of the hub driver
responsible for remote wakeup of root hubs.  When these wakeups occur
the driver is suspended, and in case the resume fails the driver should
remain suspended -- it shouldn't try to proceed with its normal
processing.

This will hardly ever matter in normal use, but it did crop up while I
was debugging a different problem.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      2425e9fe
    • A
      [PATCH] USB: Store port number in usb_device · 12c3da34
      由 Alan Stern 提交于 
      This patch (as610) adds a field to struct usb_device to store the device's
port number.  This allows us to remove several loops in the hub driver
(searching for a particular device among all the entries in the parent's
array of children).
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      12c3da34
    • A
      [PATCH] USB: Consider power budget when choosing configuration · 55c52718
      由 Alan Stern 提交于 
      This patch (as609) changes the way we keep track of power budgeting for
USB hubs and devices, and it updates the choose_configuration routine to
take this information into account.  (This is something we should have
been doing all along.)  A new field in struct usb_device holds the amount
of bus current available from the upstream port, and the usb_hub structure
keeps track of the current available for each downstream port.

Two new rules for configuration selection are added:

	Don't select a self-powered configuration when only bus power
	is available.

	Don't select a configuration requiring more bus power than is
	available.

However the first rule is #if-ed out, because I found that the internal
hub in my HP USB keyboard claims that its only configuration is
self-powered.  The rule would prevent the configuration from being chosen,
leaving the hub & keyboard unconfigured.  Since similar descriptor errors
may turn out to be fairly common, it seemed wise not to include a rule
that would break automatic configuration unnecessarily for such devices.

The second rule may also trigger unnecessarily, although this should be
less common.  More likely it will annoy people by sometimes failing to
accept configurations that should never have been chosen in the first
place.

The patch also changes usbcore's reaction when no configuration is
suitable.  Instead of raising an error and rejecting the device, now
the core will simply leave the device unconfigured.  People can always
work around such problems by installing configurations manually through
sysfs.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      55c52718
    • A
      [PATCH] USB: Fix locking for USB suspend/resume · 4bf0ba86
      由 Alan Stern 提交于 
      The earlier USB locking updates didn't touch the suspend/resume
routines.  They need updating as well, since now the caller holds the
device semaphore.  This patch (as608) makes the necessary changes.  It
also adds a line to store the correct power state when a device is
resumed, something which was unaccountably missing.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      4bf0ba86