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)
Now that devfs is removed, there's no longer any need to document how to
do this or that with devfs.
This patch includes some improvements by Joe Perches.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
The purpose of this patch is to split off the case when a device does
not reply on the lower level (which is reported by HC hardware), and
a case when the device accepted the request, but does not reply at
upper level. This redefinition allows to diagnose issues easier,
without asking the user if the -110 happened "immediately".
The usbmon splits such cases already thanks to its timestamp, but
it's not always available.
I adjusted all drivers which I found affected (by searching for "urb").
Out of tree drivers may suffer a little bit, but I do not expect much
breakage. At worst they may print a few messages.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The compat_ioctl support of the pwc driver was dropped during the last update of the driver.
I suppose it was by mistake. If yes here is the patch to restore the support.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@looxix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This patch makes the following needlessly global code static:
- pwc-ctrl.c: pwc_get_leds()
- pwc_preferred_compression
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Uneeded extern prototype is removed, as the function is
prototyped at media/v4l2-common.h.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
The videodev.h and videodev2.h describe the public API for V4L and V4L2.
It shouldn't have there any kernel-specific stuff. Those were moved to
v4l2-dev.h.
This patch removes some uneeded headers and include v4l2-common.h on all
V4L driver. This header includes device implementation of V4L2 API provided
on v4l2-dev.h as well as V4L2 internal ioctls that provides connections
between master driver and its i2c devices.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
moved from if to ifndef.
Also added such tests at gentree script. Gentree updated to its latest
version.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Add v4l2 compatibility
Include the decompressor (legal problem has been resolv by Alan Cox)
Faster decoder and easier to maintain, optimize, ...
Can export to userland compressed stream
Support more cameras, lot of bugs are fixed.
Signed-off-by: Luc Saillard <luc@saillard.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
V4L1 API is depreciated and should be removed soon from kernel. This patch
adds two new options, one to disable V4L1 drivers, and another to disable
V4L1 compat module. This way, it would be easy to check what still depends
on V4L1 stuff, allowing also to test if app works fine with V4L2 only support.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Because of historic reasons, there are two separate directories with
V4L stuff. Most drivers are located at driver/media/video. However, some
code for USB Webcams were inserted under drivers/usb/media.
This makes difficult for module authors to know were things should be.
Also, makes Kconfig menu confusing for normal users.
This patch moves all V4L content under drivers/usb/media to
drivers/media/video, and fixes Kconfig/Makefile entries.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
