litmus2008.git/drivers/usb/host/ehci-hcd.c, branch start

EHCI: Fix root-hub and port suspend/resume problems

2006-12-01T22:25:52+00:00

This patch (as738b) fixes numerous problems in the controller/root-hub
suspend/resume/remote-wakeup support in ehci-hcd:

	The bus_resume() routine should wake up only the ports that
	were suspended by bus_suspend().  Ports that were already
	suspended should remain that way.

	The interrupt mask is used to detect loss of power in the
	bus_resume() routine (if the mask is 0 then power was lost).
	However bus_suspend() always sets the mask to 0.  Instead the
	mask should retain its normal value, with port-change-detect
	interrupts disabled if remote wakeup is turned off.

	The interrupt mask should be reset to its correct value at the
	end of bus_resume() regardless of whether power was lost.

	bus_resume() reinitializes the operational registers if power
	was lost.  However those registers are not in the aux power
	well, hence they can lose their values whenever the controller
	is put into D3.  They should always be reinitialized.

	When a port-change interrupt occurs and the root hub is
	suspended, the interrupt handler should request a root-hub
	resume instead of starting up the controller all by itself.

	There's no need for the interrupt handler to request a
	root-hub resume every time a suspended port sends a
	remote-wakeup request.

	The pci_resume() method doesn't need to check for connected
	ports when deciding whether or not to reset the controller.
	It can make that decision based on whether Vaux power was
	maintained.

	Even when the controller does not need to be reset,
	pci_resume() must undo the effect of pci_suspend() by
	re-enabling the interrupt mask.

	If power was lost, pci_resume() must not call ehci_run().
	At this point the root hub is still supposed to be suspended,
	not running.  It's enough to rewrite the command register and
	set the configured_flag.

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

USB: add ehci_hcd.ignore_oc parameter

2006-12-01T22:23:37+00:00

Certain boards seem to like to issue false overcurrent notifications, for
example on ports that don't have anything connected to them.  This looks
like a hardware error, at the level of noise to those ports' overcurrent
input signals (or non-debounced VBUS comparators).  This surfaces to users
as truly massive amounts of syslog spam from khubd (which is appropriate
for real hardware problems, except for the volume from multiple ports).

Using this new "ignore_oc" flag helps such systems work more sanely, by
preventing such indications from getting to khubd (and spam syslog).  The
downside is of course that true overcurrent errors will be masked; they'll
appear as spontaneous disconnects, without the diagnostics that will let
users troubleshoot issues like short circuited cables.

Note that the bulk of these reports seem to be with VIA southbridges, but
I think some were with Intel ones.

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

USB: revert EHCI VIA workaround patch

2006-10-17T20:57:18+00:00

This reverts 26f953fd884ea4879585287917f855c63c6b2666 which caused
resume problems on the mac mini.

Cc: David Brownell 
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)

USB: EHCI update VIA workaround

2006-09-27T18:59:00+00:00

This revamps handling of the hardware "async advance" IRQ, and its watchdog
timer.  Basically it dis-entangles that important timeout from the others,
simplifying the associated state and code to make it more robust.

This reportedly improves behavior of EHCI on some systems with VIA chips,
and AFAIK won't affect non-VIA hardware.  VIA systems need this code to
recover from silcon bugs whereby the "async advance" IRQ isn't issued.

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

USB: EHCI whitespace fixes (cosmetic)

2006-09-27T18:58:56+00:00

[ ... when you have an editor set to remind you of whitespace bugs ... ]

Cosmetic EHCI changes: remove end-of-line whitespace, spaces before tabs.

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

USB: Properly unregister reboot notifier in case of failure in ehci hcd

2006-09-27T18:58:54+00:00

If some problem occurs during ehci startup, for instance, request_irq fails,
echi hcd driver tries it best to cleanup, but fails to unregister reboot
notifier, which in turn leads to crash on reboot/poweroff.

The following patch resolves this problem by not using reboot notifiers
anymore, but instead making ehci/ohci driver get its own shutdown method.  For
PCI, it is done through pci glue, for everything else through platform driver
glue.

One downside: sa1111 does not use platform driver stuff, and does not have its
own shutdown hook, so no 'shutdown' is called for it now.  I'm not sure if it
is really necessary on that platform, though.

Signed-off-by: Aleks Gorelov 
Cc: Alan Stern 
Cc: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

USB: Fix Freescale high-speed USB host dependency

2006-08-02T23:41:41+00:00

The high-speed USB SOC only exists on MPC834x family not MPC83xx family.

Signed-off-by: Li Yang 
Acked-by: Kumar Gala 
Signed-off-by: Greg Kroah-Hartman

[PATCH] USB: ehci: fix bogus alteration of a local variable

2006-07-12T23:03:23+00:00

In a rare and all-but-unused path, the EHCI driver could reuse a variable
in a way that'd make trouble.  Specifically, if the first root hub port
gets an overcurrent event (rare) during a remote wakeup scenario (all but
unused in today's Linux, except for folk working with suspend-to-RAM and
similar sleep states), that would look like a fatal error which would shut
down the controller.  Fix by not reusing that variable.

Spotted by Per Hallsmark 
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=6661

Signed-off-by: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

Remove obsolete #include

2006-06-30T17:25:36+00:00

Signed-off-by: Jörn Engel 
Signed-off-by: Adrian Bunk