People have been reporting that PPP connections over ptys, such as
used with PPTP, will hang randomly when transferring large amounts of
data, for instance in http://bugzilla.kernel.org/show_bug.cgi?id=6530.
I have managed to reproduce the problem, and the patch below fixes the
actual cause.
The problem is not in fact in ppp_async.c but in n_tty.c. What
happens is that when pptp reads from the pty, we call read_chan() in
drivers/char/n_tty.c on the master side of the pty. That copies all
the characters out of its buffer to userspace and then calls
check_unthrottle(), which calls the pty unthrottle routine, which
calls tty_wakeup on the slave side, which calls ppp_asynctty_wakeup,
which calls tasklet_schedule. So far so good. Since we are in
process context, the tasklet runs immediately and calls
ppp_async_process(), which calls ppp_async_push, which calls the
tty->driver->write function to send some more output.
However, tty->driver->write() returns zero, because the master
tty->receive_room is still zero. We haven't returned from
check_unthrottle() yet, and read_chan() only updates tty->receive_room
_after_ calling check_unthrottle. That means that the driver->write
call in ppp_async_process() returns 0. That would be fine if we were
going to get a subsequent wakeup call, but we aren't (we just had it,
and the buffer is now empty).
The solution is for n_tty.c to update tty->receive_room _before_
calling the driver unthrottle routine. The patch below does this.
With this patch I was able to transfer a 900MB file over a PPTP
connection (taking about 25 minutes), whereas without the patch the
connection would always stall in under a minute.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
From: Milton Miller <miltonm@bga.com>
The add_preferred_console call in rtas_console.c was not causing the
console to be selected. It turns out that the add_preferred_console was
being called after the hvc_console driver was registered. It only works
when it is called before the console driver is registered.
Reorder hvc_console.o after the hvc_console drivers to allow the selection
during console_initcall processing.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A few cleanups in hvc_rtas.c:
1. Remove unused RTASCONS_PUT_ATTEMPTS
2. Remove unused rtascons_put_delay.
3. Use i as a loop counter like everyone else on earth.
4. Remove pointless variables, eg. x = foo; if (x) return something_else;
5. Whitespace cleanups and formatting.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Currently the hvc_rtas driver is painfully slow to use. Our "benchmark" is
ls -R /etc, which spits out about 27866 characters. The theoretical maximum
speed would be about 2.2 seconds, the current code takes ~50 seconds.
The core of the problem is that sometimes when the tty layer asks us to push
characters the firmware isn't able to handle some or all of them, and so
returns an error. The current code sees this and just returns to the tty code
with the buffer half sent.
The khvcd thread will eventually wake up and try to push more characters, which
will usually work because by then the firmware's had time to make room. But
the khvcd thread only wakes up every 10 milliseconds, which isn't fast enough.
So change the khvcd thread logic so that if there's an incomplete write we
yield() and then immediately try writing again. Doing so makes POLL_QUICK and
POLL_WRITE synonymous, so remove POLL_QUICK.
With this patch our "benchmark" takes ~2.8 seconds.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
drivers/char/agp/alpha-agp.c:138: warning: initialization from incompatible pointer type
drivers/char/agp/alpha-agp.c:139: warning: initialization from incompatible pointer type
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
drivers/char/agp/uninorth-agp.c: In function `agp_uninorth_suspend':
drivers/char/agp/uninorth-agp.c:332: warning: cast to pointer from integer of different size
drivers/char/agp/uninorth-agp.c: In function `agp_uninorth_resume':
drivers/char/agp/uninorth-agp.c:354: warning: cast from pointer to integer of different size
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Fix the incorrect calculation of how much to zero out in struct cm4000_dev
on device initialization.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
From: Andrew Morton <akpm@osdl.org>
Revert commit ff4da2e262.
It broke APM suspend, probably because APM doesn't switch back to a VT
when suspending.
Tracked down by Matt Mackall <mpm@selenic.com>
Rafael sayeth:
"It only fixed the theoretical issue that a quick-handed user could
switch to X after processes have been frozen and before the devices
are suspended.
With the current userland suspend tools it shouldn't be necessary."
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
From: Corey Minyard <minyard@acm.org>
This patch is pretty important to get in for IPMI, new systems have been
changing the way ACPI and IPMI interact, and this works around the problems
for now. This is a temporary fix until we get proper ACPI handling in
IPMI.
Fixed releasing already-allocated regions when a later request fails, and
forward-ported it to HEAD.
Some BIOSes reserve disjoint I/O regions in their ACPI tables for the IPMI
controller. This causes problems when trying to register the entire I/O
region. Therefore we must register each I/O port separately.
Signed-off-by: Jordan Hargrave <Jordan_Hargrave@dell.com>
Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
From: Seiji Munetoh <seiji.munetoh@gmail.com>
Change the binary output format to actual ACPI TCPA log structure since the
current format does not contain all event-data information that need to
verify the PCRs in TPM. tpm_binary_bios_measurements_show() uses
get_event_name() to convert the binary event-data to ascii format, and puts
them as binary. However, to verify the PCRs, the event-data must be a
actual binary event-data used by SHA1 calc. in BIOS.
So, I think actual ACPI TCPA log is good for this binary output format.
That way, any userland tools easily parse this data with reference to TCG
PC specification.
Signed-off-by: Seiji Munetoh <seiji.munetoh@gmail.com>
Acked-by: Kylene Hall <kjhall@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* master.kernel.org:/pub/scm/linux/kernel/git/davej/agpgart:
[AGPGART] VIA PT880 Ultra support.
[AGPGART] Fix Nforce3 suspend on amd64.
[AGPGART] Enable SIS AGP driver on x86-64 for EM64T systems
