The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.
This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.
When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.
For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).
Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.
The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.
I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.
Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real. That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.
Description:
tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification]. It
does now also return the number of chars inserted
There are also
tty_buffer_request_room(tty, len)
which asks for a buffer block of the length requested and returns the space
found. This improves efficiency with hardware that knows how much to
transfer.
and tty_insert_flip_string_flags(tty, str, flags, len)
to insert a string of characters and flags
For a smart interface the usual code is
len = tty_request_buffer_room(tty, amount_hardware_says);
tty_insert_flip_string(tty, buffer_from_card, len);
More description!
At the moment tty buffers are attached directly to the tty. This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)
I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers. This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.
So far so good. Lots of drivers reference tty->flip.*. Several of them also
call directly and unsafely into function pointers it provides. This will all
break. Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.
At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say
int tty_buffer_request_room(tty, size)
Try and ensure at least size bytes are available, returns actual room (may be
zero). At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative. (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space. The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.
int tty_insert_flip_char(tty, ch, flag)
As before insert a character if there is room. Now returns 1 for success, 0
for failure.
int tty_insert_flip_string(tty, str, len)
Insert a block of non error characters. Returns the number inserted.
int tty_prepare_flip_string(tty, strptr, len)
Adjust the buffer to allow len characters to be added. Returns a buffer
pointer in strptr and the length available. This allows for hardware that
needs to use functions like insl or mencpy_fromio.
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I looked at the userspace code which uses the LPIOC_GET_DEVICE_ID ioctl
and I almost went blind. Let's export it in sysfs instead, and just as a
string instead of with a big-endian length at the beginning of it.
This also prints the message about finding the printer _after_ we know
the minor device number it's going to have, rather than reporting all
printers as 'usblp0'.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
From: David Woodhouse <dwmw2>
David has a G5 with a printer. I am quite surprised that nobody else noticed
this before. Linus has a G5. Hackers hate printing in general, maybe.
We do not use BKL anymore, because one of code paths had a sleeping call,
so we had to use a semaphore. I am sure it's safe to use unlocked_ioctl.
The new ioctls return long and retval is int. It looks completely fine to me.
We never want these extra bits, and the sign extension ought to work right.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--
patch below marks various USB tables and variables as const so that they
end up in .rodata section and don't cacheline share with things that get
written to. For the non-array variables it also allows gcc to optimize
more.
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
this patch by David converts the sending queue of the CDC ACM driver
to a queue of URBs. This is needed for quicker devices. Please apply.
Signed-Off-By: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/class/cdc-acm.c | 229 ++++++++++++++++++++++++++++++--------------
drivers/usb/class/cdc-acm.h | 33 +++++-
2 files changed, 185 insertions(+), 77 deletions(-)
This patch removes all references to the bouncing address
rddunlap@osdl.org and one dead web page from the kernel.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
We have a real Bluetooth system in Linux, lets finally delete this driver as no
one is using it (and if they are, they are using a closed source bluetooth
stack, which I can't support anyway.)
Marcel, you owe me a beer :)
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Deprecate the OSS USB drivers.
This patch includes spelling fixes by Lee Revell.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Rate-limit usblp printer error status messages.
I unplugged my USB printer and almost instantly got several hundred
of these in my kernel message log:
drivers/usb/class/usblp.c: usblp0: error -19 reading printer status
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch enables a support of KYOCERA AH-K3001V, one of the most
popular cell phone in Japan. This device has vendor specific ID but works
with acm driver by adding USB ID. This device already works on
FreeBSD and OS X by native USB ACM driver with USB ID added.
This device is probed as NO_UNION_NORMAL not to hang up when probing.
Signed-off-by: Masahito Omote <omote@utyuuzin.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This increases the reference count on the usb cdc acm control interface
which is referred to by the tty interface provided by the driver. This
allows the deferred removal of the tty after the physical device is
disconnected if the tty is held open at the time of disconnection.
Signed-off-by: brian@murphy.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
up(&usblp->sem) was called twice in a row in this code path.
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Initialize status fields in the read and write urbs to prevent a race
condition with open/read/close - open/write/close sequences.
Fixes bug #4432 at bugzilla.kernel.org
Signed-off-by: Adam Oldham <oldhamca@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixes lost LF when ACM device is used with getty/login/bash,
in case of a modem which takes calls.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Get rid of a bunch of redundant NULL pointer checks in drivers/usb/*,
there's no need to check a pointer for NULL before calling kfree() on it.
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Index: gregkh-2.6/drivers/usb/class/audio.c
===================================================================
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
