linux/drivers/char
Hendrik Brueckner 7f8030d166 hvc_console: Remove tty->low_latency
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>
2009-01-16 16:15:16 +11:00
..
agp agp/intel: Fix broken ® symbol in device name. 2008-12-29 10:06:20 +10:00
hw_random sparc64: Fix unsigned long long warnings in drivers. 2009-01-06 13:20:38 -08:00
ip2 device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
ipmi Fix platform drivers that crash on suspend/resume 2008-11-12 17:17:16 -08:00
mwave mwave: struct device - replace bus_id with dev_name(), dev_set_name() 2009-01-06 10:44:38 -08:00
pcmcia synclink_cs: Convert to tty_port 2009-01-02 10:19:42 -08:00
rio rio: Kill off ckmalloc 2009-01-02 10:19:38 -08:00
tpm Merge branch 'linus' into release 2009-01-09 03:39:43 -05:00
xilinx_hwicap xilinx_hwicap: remove improper wording in license statement 2008-12-17 11:23:07 -08:00
.gitignore
amiserial.c m68k: amiserial - Kill warn_unused_result warnings 2009-01-12 20:56:39 +01:00
apm-emulation.c APM emulation: Notify about all suspend events, not just APM invoked ones (v2) 2008-07-16 23:27:02 +02:00
applicom.c applicom.c: fix apparently-broken code in do_ac_read() 2008-10-16 11:21:47 -07:00
applicom.h
bfin-otp.c Blackfin char driver for Blackfin on-chip OTP memory (v3) 2008-04-25 08:04:56 +08:00
briq_panel.c briq_panel: BKL pushdown 2008-06-20 14:05:55 -06:00
bsr.c powerpc: Cleanup from l64 to ll64 change: drivers/char 2009-01-13 14:48:00 +11:00
cd1865.h
ChangeLog
consolemap.c consolemap: indentation & braces disagree - reindent 2009-01-06 15:59:30 -08:00
cp437.uni unicode table for cp437 2008-12-13 11:25:49 -08:00
cs5535_gpio.c Add a bunch of cycle_kernel_lock() calls 2008-06-20 14:05:53 -06:00
cyclades.c drivers/char/cyclades.c: cy_pci_probe: fix error path 2009-01-02 10:19:43 -08:00
defkeymap.c_shipped Fix default compose table initialization 2008-03-03 14:53:16 -08:00
defkeymap.map
digi1.h
digiFep1.h
digiPCI.h
ds1302.c rtc: use bcd2bin/bin2bcd 2008-10-20 08:52:41 -07:00
ds1620.c [ARM] netwinder: clean up GPIO naming 2008-12-13 09:12:07 +00:00
dsp56k.c device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
dtlk.c Add a bunch of cycle_kernel_lock() calls 2008-06-20 14:05:53 -06:00
efirtc.c drivers/char/efirtc.c: removed duplicated #include 2008-08-04 16:59:56 -07:00
epca.c trivial: fix an -> a typos in documentation and comments 2009-01-06 11:28:07 +01:00
epca.h epca: use tty_port 2008-07-20 17:12:36 -07:00
epcaconfig.h
esp.c tty_port: Add a port level carrier detect operation 2009-01-02 10:19:38 -08:00
generic_nvram.c driver/char/generic_nvram: fix banner 2008-06-12 18:05:41 -07:00
generic_serial.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
genrtc.c genrtc: BKL pushdown 2008-06-20 14:05:57 -06:00
hangcheck-timer.c
hpet.c x86: correct link to HPET timer specification 2008-11-24 10:05:12 +01:00
hvc_beat.c powerpc/cell: Use correct types in beat files 2009-01-08 16:25:16 +11:00
hvc_console.c hvc_console: Remove tty->low_latency 2009-01-16 16:15:16 +11:00
hvc_console.h powerpc: Make open count variables signed in hvcs/hvsi/hvc_console 2008-12-03 21:04:13 +11:00
hvc_irq.c hvc_console: Call free_irq() only if request_irq() was successful 2009-01-13 14:48:01 +11:00
hvc_iseries.c drivers/hvc: Add missing of_node_put 2008-12-03 21:04:09 +11:00
hvc_iucv.c [S390] hvc_iucv: Special handling of IUCV HVC devices 2009-01-09 12:15:09 +01:00
hvc_rtas.c [POWERPC] hvc_rtas_init() must be __init 2008-02-14 22:11:02 +11:00
hvc_udbg.c powerpc: udbg-based backend for hvc_console 2008-11-19 16:04:25 +11:00
hvc_vio.c drivers/hvc: Add missing of_node_put 2008-12-03 21:04:09 +11:00
hvc_xen.c hvc_console: Add a hangup notifier for backends 2008-10-22 10:59:54 +11:00
hvcs.c powerpc: Make open count variables signed in hvcs/hvsi/hvc_console 2008-12-03 21:04:13 +11:00
hvsi.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
i8k.c i8k: Add Dell Vostro systems 2009-01-02 10:28:32 -08:00
isicom.c tty: Introduce some close helpers for ports 2009-01-02 10:19:40 -08:00
istallion.c tty: Introduce some close helpers for ports 2009-01-02 10:19:40 -08:00
Kconfig powerpc: Fix iseries drivers build failure without CONFIG_VIOPATH 2009-01-08 16:25:14 +11:00
keyboard.c Input: keyboard - fix potential out of bound access to key_map 2008-10-08 23:45:36 -04:00
lp.c device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
Makefile Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-12-28 16:54:33 -08:00
mbcs.c mbcs: cdev lock_kernel() pushdown 2008-06-20 14:05:48 -06:00
mbcs.h MBCS: convert dmareadlock to mutex 2008-02-07 08:42:25 -08:00
mem.c mm: make vread() and vwrite() declaration 2009-01-06 15:59:05 -08:00
misc.c device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
mmtimer.c mmtimer: Push BKL down into the ioctl handler 2008-07-17 11:34:49 -07:00
moxa.c tty_port: Add a port level carrier detect operation 2009-01-02 10:19:38 -08:00
moxa.h Char: moxa, cleanup rx/tx 2008-04-30 08:29:43 -07:00
mspec.c mspec: convert nopfn to fault 2008-07-24 10:47:14 -07:00
mxser.c tty: Introduce some close helpers for ports 2009-01-02 10:19:40 -08:00
mxser.h mxser: convert large macros to functions 2008-04-30 08:29:49 -07:00
n_hdlc.c tty: some ICANON magic is in the wrong places 2008-10-13 09:51:44 -07:00
n_r3964.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
n_tty.c tty: N_TTY SIGIO only works for read 2009-01-02 10:19:40 -08:00
nozomi.c tty: kref nozomi 2009-01-02 10:19:40 -08:00
nsc_gpio.c
nvram.c [PATCH] nvram - convert PRINT_PROC to seq_file 2008-11-11 09:56:00 +00:00
nwbutton.c
nwbutton.h
nwflash.c [ARM] netwinder: clean up GPIO naming 2008-12-13 09:12:07 +00:00
pc8736x_gpio.c pc8736x_gpio: add support for PC87365 chips 2008-10-20 08:52:40 -07:00
ppdev.c device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
ps3flash.c powerpc/ps3: Printing fixups for l64 to ll64 conversion drivers/char 2009-01-16 16:15:14 +11:00
pty.c pty: Fix documentation 2009-01-12 16:37:00 -08:00
random.c random: don't try to look at entropy_count outside the lock 2009-01-06 15:59:30 -08:00
raw.c [PATCH] kill the rest of struct file propagation in block ioctls 2008-10-21 07:49:14 -04:00
riscom8_reg.h
riscom8.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
riscom8.h tty: add more tty_port fields 2008-07-20 17:12:38 -07:00
rocket_int.h tty: rocketport uses different port flags to everyone else 2009-01-02 10:19:39 -08:00
rocket.c tty: use port methods for the rocket driver 2009-01-02 10:19:42 -08:00
rocket.h tty: rocketport uses different port flags to everyone else 2009-01-02 10:19:39 -08:00
rtc.c RTC: Remove the BKL. 2009-01-08 16:44:03 -07:00
scc.h
scx200_gpio.c Add a bunch of cycle_kernel_lock() calls 2008-06-20 14:05:53 -06:00
selection.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
ser_a2232.c m68k: ser_a2232 - Kill warn_unused_result warnings 2009-01-12 20:56:39 +01:00
ser_a2232.h
ser_a2232fw.ax
ser_a2232fw.h
serial167.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
snsc_event.c byteorder: don't directly include linux/byteorder/generic.h 2008-05-16 12:01:45 -07:00
snsc.c device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
snsc.h Convert asm/semaphore.h users to linux/semaphore.h 2008-04-18 22:22:54 -04:00
sonypi.c Merge branch 'misc' into release 2008-11-11 21:14:11 -05:00
specialix_io8.h tty: add more tty_port fields 2008-07-20 17:12:38 -07:00
specialix.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
stallion.c tty: Introduce some close helpers for ports 2009-01-02 10:19:40 -08:00
sx.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
sx.h Char: char/serial, remove SERIAL_TYPE_NORMAL redefines 2008-02-07 08:42:33 -08:00
sxboards.h
sxwindow.h
synclink_gt.c synclink_gt: enable RI interrupt 2009-01-15 16:39:37 -08:00
synclink.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
synclinkmp.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
sysrq.c sysrq: add commentary on why we use the console loglevel over using KERN_EMERG 2009-01-15 16:39:36 -08:00
tb0219.c Add a bunch of cycle_kernel_lock() calls 2008-06-20 14:05:53 -06:00
tlclk.c tlckl: BKL pushdown 2008-06-20 14:05:51 -06:00
toshiba.c toshiba: use ioremap_cached 2008-04-30 23:15:34 +02:00
tty_audit.c Audit: Log TIOCSTI 2008-12-09 20:32:06 +11:00
tty_buffer.c tty: split the buffering from tty_io 2008-10-13 09:51:40 -07:00
tty_io.c pty: simplify resize 2009-01-02 10:19:36 -08:00
tty_ioctl.c tty: Fix race in the flush for some ldiscs 2009-01-15 12:48:35 -08:00
tty_ldisc.c tty: Fix PPP hang under load 2009-01-02 10:19:38 -08:00
tty_port.c tty: use port methods for the rocket driver 2009-01-02 10:19:42 -08:00
vc_screen.c device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
viotape.c device create: char: convert device_create_drvdata to device_create 2008-10-16 09:24:42 -07:00
virtio_console.c virtio_console: support console resizing 2008-12-30 09:26:10 +10:30
vme_scc.c m68k: vme_scc - Kill warn_unused_result warnings 2009-01-12 20:56:38 +01:00
vr41xx_giu.c drivers/char: use nr_irqs 2008-10-16 16:52:05 +02:00
vt_ioctl.c tty: Remove some pointless casts 2009-01-02 10:19:40 -08:00
vt.c Make various things static 2009-01-08 08:31:15 -08:00