This patch removes the tty->low_latency setting.
For irq based hvc_console backends the tty->low_latency must be set to 0,
because the tty_flip_buffer_push() function must not be called from IRQ context
(see drivers/char/tty_buffer.c).
For polled backends, the low_latency setting causes the bug trace below, because
tty_flip_buffer_push() is called within an atomic context and subsequent calls
might sleep due to mutex_lock.
BUG: sleeping function called from invalid context at /root/cvs/linux-2.6.git/kernel/mutex.c:207
in_atomic(): 1, irqs_disabled(): 0, pid: 748, name: khvcd
1 lock held by khvcd/748:
#0: (hvc_structs_lock){--..}, at: [<00000000002ceb50>] khvcd+0x58/0x12c
CPU: 0 Not tainted 2.6.29-rc1git #29
Process khvcd (pid: 748, task: 000000002fb9a480, ksp: 000000002f66bd78)
070000000000000a 000000002f66ba00 0000000000000002 (null)
000000002f66baa0 000000002f66ba18 000000002f66ba18 0000000000104f08
ffffffffffffc000 000000002f66bd78 (null) (null)
000000002f66ba00 000000000000000c 000000002f66ba00 000000002f66ba70
0000000000466af8 0000000000104f08 000000002f66ba00 000000002f66ba50
Call Trace:
([<0000000000104e7c>] show_trace+0x138/0x158)
[<0000000000104f62>] show_stack+0xc6/0xf8
[<0000000000105740>] dump_stack+0xb0/0xc0
[<000000000013144a>] __might_sleep+0x14e/0x17c
[<000000000045e226>] mutex_lock_nested+0x42/0x3b4
[<00000000002c443e>] echo_char_raw+0x3a/0x9c
[<00000000002c688c>] n_tty_receive_buf+0x1154/0x1208
[<00000000002ca0a2>] flush_to_ldisc+0x152/0x220
[<00000000002ca1da>] tty_flip_buffer_push+0x6a/0x90
[<00000000002cea74>] hvc_poll+0x244/0x2c8
[<00000000002ceb68>] khvcd+0x70/0x12c
[<000000000015bbd0>] kthread+0x68/0xa0
[<0000000000109d5a>] kernel_thread_starter+0x6/0xc
[<0000000000109d54>] kernel_thread_starter+0x0/0xc
1 lock held by khvcd/748:
#0: (hvc_structs_lock){--..}, at: [<00000000002ceb50>] khvcd+0x58/0x12c
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Also a couple of min -> min_t changes.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
- Enable ring indicator interrupt.
- Remove vendor specific CVS version tags.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add an explanitory comment as to why we modify the kernel console loglevel
rather than simply moving sysrq messages to KERN_EMERG level.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If you issue an ioctl to flush a tty as the line discipline is changing or
otherwise unplugged you can get a crash. The bug is very old but the rest
of the BKL lock dropping and some very "good" luck on Ingo's part caught
an example.
Use the correct ldisc_ref form so that we wait for the ldisc change to
complete and then flush
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace kmalloc() + memset() with kzalloc().
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
hvc_console is setting low_latency unconditionally, but some clients are
interrupt driven and will call hvc_poll from irq context. This will cause
tty_flip_buffer_push to be called from irq context, and it very clearly
states it must not be called from IRQ when low_latency is specified.
Looking back through history:
v2.6.16-rc1 via 33f0f88f1c
[PATCH] TTY layer buffering revamp
added this new api.
v2.6.16-rc3 via 8977d929e4
[PATCH] tty buffering stall fix
claims to fix a stall discovered with hvc_console
v2.6.16-rc5 via fb5c594c2a
[PATCH] Fix race condition in hvc console.
said set this flag to avoid a stall problem, and was merged through
the powerpc arch tree.
Without searching for email discussions, it would appear to be an
overlapping "fix", but one that did not consider all users.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Only call free_irq if we marked the request_irq has having succeeded
instead of whenever the the sub-driver identified the interrupt to use.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
I remember some history on this barrier. There was a race between
open via /dev/console and the tty being fully setup. Its also why
there is a temporary variable and the global is assigned at the end
of the function.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This is a powerpc specific driver.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The pty changes and updates for window sizing forgot to correct the
kerneldoc
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
warning: ignoring return value of 'request_irq', declared with attribute
warn_unused_result
and clean up the error path handling.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
warning: ignoring return value of 'request_irq', declared with attribute
warn_unused_result
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
warning: ignoring return value of 'request_irq', declared with attribute
warn_unused_result
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
This patch introduces special handling of the IUCV HVC console device.
If the first IUCV HVC terminal is used as (preferred) Linux console, and
needs some special handling for hangup.
The hvc_iucv_private structure contains a flag to indicate whether a IUCV
HVC device is used as a console.
A terminal acting as "console" behaves different if a tty hangup occurs:
If the iucv communication path is severed, a tty hangup is not
triggered (because the HVC layer does not notify its back-end in that case).
Instead, the console session is left unchanged and the IUCV HVC device is
reset to allow re-connects.
Note: Any output between the disconnect and a re-connect is discarded.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The console_initcall() order might pick up the hvc_iucv device as preferred
console even if it is not yet initialized.
Move HVC console instantiation to hvc_iucv_init() and cleanup device driver
initialization.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Update documentation of functions.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This patch introduces a send buffer to limit outgoing IUCV messages up to
a maximum of 25 IUCV messages per second.
If no communication path to a IUCV HVC terminal exist, any data written to
the terminal is discarded.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The patch renames the IUCV application ID from "ihvc" to "lnxhvc".
The device driver allocates one IUCV terminal device (lnxhvc0) as default.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove calls to the BKL since concurrent access is protected
by the spin lock rtc_lock.
Signed-off-by: David John <davidjon@xenontk.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Building an allnoconfig kernel, sparse asked whether these could be
static, so I checked, and they are only used in the file where they are
declared.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Only pass the address of a u64 if that is what the function requires.
[Split out of a larger patch - sfr]
[update comment - sfr]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
iSeries dependent drivers fail to build, when CONFIG_VIOPATH is disabled.
Fix the problem by making those drivers select it.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
As a non-atomic value, it's only safe to look at entropy_count when the
pool lock is held, so we move the BUG_ON inside the lock for correctness.
Also remove the spurious comment. It's ok for entropy_count to
temporarily exceed POOLBITS so long as it's left in a consistent state
when the lock is released.
This is a more correct, simple, and idiomatic fix for the bug in
8b76f46a2d. I've left the reorderings introduced by that patch in place
as they're harmless, even though they don't properly deal with potential
atomicity issues.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Blackfin platforms do not support the hardware which this driver drives.
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Eliminate sysrq terse help mode; make sysrq help messages more meaningful
(more explicit/verbose). Make the sysrq action letter clearer by listing
it explicitly in more sysrq help messages (when it is not simple/clear).
The SysRq help message now looks like this:
SysRq : HELP : loglevel(0-9) reBoot terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) saK show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers(P) show-all-timers(Q) unRaw Sync show-task-states(T) Unmount show-blocked-tasks(W)
Addresses http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=330403.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: <jidanni@jidanni.org>
Cc: <330403@bugs.debian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sparse output following warnings.
mm/vmalloc.c:1436:6: warning: symbol 'vread' was not declared. Should it be static?
mm/vmalloc.c:1474:6: warning: symbol 'vwrite' was not declared. Should it be static?
However, it is used by /dev/kmem. fixed here.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix warnings caused by the unsigned long long usage in sparc
specific drivers.
The drivers were considered sparc specific more or less from the
filename alone.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is always "an" if there is a vowel _spoken_ (not written).
So it is:
"an hour" (spoken vowel)
but
"a uniform" (spoken 'j')
Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
those two functions only used in that C file
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This trivial patch adds support for i8k on the new Dell Vostro models.
I tested it on my Vostro 1400, and it works. It does print a warning
when loading the module:
i8k: unable to get SMM BIOS version
But I couldn't figure out how to fix that. The module seems to work fine,
anyway...
Signed-off-by: Federico Heinz <fheinz@vialibre.org.ar>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch to enable i8k on Dell Precisions.
Signed-off-by: Andy Spencer <spenceal@rose-hulman.edu>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We forgot to release resources in one case.
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12137
Reported-by: Florian Lohoff <flo@rfc822.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the tty port operations, add refcounting, and refactor a bit to make the
refcounting work cleanly.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now we have our ducks in order we can begin switching to the port
operations
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We will need this kref fitted to make full use of the port operations.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to this ready for using the standard helpers
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now the locking is straight and the port kref usage is straight we can
replace lots of chunks of code with the standard port helpers
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The write wakeup is done anyway for the poll while DO_WRITE_WAKUP is
cleared, set and managed by the ldisc layer and is no business of the pty
code.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The N_TTY ldisc layer does not send SIGIO POLL_OUTs correctly when output is
possible due to flawed handling of the TTY_DO_WRITE_WAKEUP bit. It will
either send no SIGIOs at all or on every tty wakeup.
The fix is to set the bit when the tty driver write would block and test
and clear it on write wakeup.
[Merged with existing N_TTY patches and a small buglet fixed -- Alan]
Signed-off-by: Thomas Pfaff <tpfaff@pcs.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Again this is a lot of common code we can unify
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If we have no speed set at some point then we should not raise DTR/RTS at
that point when opening as the tty is not ready
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hendrik Brueckner