linux/drivers/tty/ipwireless, branch v3.16

tty: Fix low_latency BUG

2014-03-01T00:31:00Z

The user-settable knob, low_latency, has been the source of several BUG reports which stem from flush_to_ldisc() running in interrupt context. Since 3.12, which added several sleeping locks (termios_rwsem and buf->lock) to the input processing path, the frequency of these BUG reports has increased. Note that changes in 3.12 did not introduce this regression; sleeping locks were first added to the input processing path with the removal of the BKL from N_TTY in commit a88a69c91256418c5907c2f1f8a0ec0a36f9e6cc, 'n_tty: Fix loss of echoed characters and remove bkl from n_tty' and later in commit 38db89799bdf11625a831c5af33938dcb11908b6, 'tty: throttling race fix'. Since those changes, executing flush_to_ldisc() in interrupt_context (ie, low_latency set), is unsafe. However, since most devices do not validate if the low_latency setting is appropriate for the context (process or interrupt) in which they receive data, some reports are due to misconfiguration. Further, serial dma devices for which dma fails, resort to interrupt receiving as a backup without resetting low_latency. Historically, low_latency was used to force wake-up the reading process rather than wait for the next scheduler tick. The effect was to trim multiple milliseconds of latency from when the process would receive new data. Recent tests [1] have shown that the reading process now receives data with only 10's of microseconds latency without low_latency set. Remove the low_latency rx steering from tty_flip_buffer_push(); however, leave the knob as an optional hint to drivers that can tune their rx fifos and such like. Cleanup stale code comments regarding low_latency. [1] https://lkml.org/lkml/2014/2/20/434 "Yay.. thats an annoying historical pain in the butt gone." -- Alan Cox Reported-by: Beat Bolli Reported-by: Pavel Roskin Acked-by: David Sterba Cc: Grant Edwards Cc: Stanislaw Gruszka Cc: Hal Murray Cc: # 3.12.x+ Signed-off-by: Peter Hurley Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman

tty: delete non-required instances of include

2014-01-08T01:05:21Z

None of these files are actually using any __init type directives and hence don't need to include . Most are just a left over from __devinit and __cpuinit removal, or simply due to code getting copied from one driver to the next. Signed-off-by: Paul Gortmaker Signed-off-by: Greg Kroah-Hartman

tty: ipwireless: Remove redundant NULL check before kfree

2013-03-15T20:58:32Z

kfree on NULL pointer is a no-op. Signed-off-by: Syam Sidhardhan Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2013-02-22T01:40:58Z

Pull trivial tree from Jiri Kosina: "Assorted tiny fixes queued in trivial tree" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (22 commits) DocBook: update EXPORT_SYMBOL entry to point at export.h Documentation: update top level 00-INDEX file with new additions ARM: at91/ide: remove unsused at91-ide Kconfig entry percpu_counter.h: comment code for better readability x86, efi: fix comment typo in head_32.S IB: cxgb3: delay freeing mem untill entirely done with it net: mvneta: remove unneeded version.h include time: x86: report_lost_ticks doesn't exist any more pcmcia: avoid static analysis complaint about use-after-free fs/jfs: Fix typo in comment : 'how may' -> 'how many' of: add missing documentation for of_platform_populate() btrfs: remove unnecessary cur_trans set before goto loop in join_transaction sound: soc: Fix typo in sound/codecs treewide: Fix typo in various drivers btrfs: fix comment typos Update ibmvscsi module name in Kconfig. powerpc: fix typo (utilties -> utilities) of: fix spelling mistake in comment h8300: Fix home page URL in h8300/README xtensa: Fix home page URL in Kconfig ...

Merge branch 'master' into for-next

2013-01-29T09:48:30Z

Conflicts: drivers/devfreq/exynos4_bus.c Sync with Linus' tree to be able to apply patches that are against newer code (mvneta).

TTY: switch tty_flip_buffer_push

2013-01-16T06:30:15Z

Now, we start converting tty buffer functions to actually use tty_port. This will allow us to get rid of the need of tty in many call sites. Only tty_port will needed and hence no more tty_port_tty_get in those paths. Now, the one where most of tty_port_tty_get gets removed: tty_flip_buffer_push. IOW we also closed all the races in drivers not using tty_port_tty_get at all yet. Also we move tty_flip_buffer_push declaration from include/linux/tty.h to include/linux/tty_flip.h to all others while we are changing it anyway. Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman

TTY: move low_latency to tty_port

2013-01-16T06:23:16Z

One point is to have less places where we actually need tty pointer. The other is that low_latency is bound to buffer processing and buffers are now in tty_port. So it makes sense to move low_latency to tty_port too. Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman

TTY: switch tty_insert_flip_string

2013-01-16T06:22:35Z

treewide: Replace incomming with incoming in all comments and strings

2013-01-03T15:15:49Z

Signed-off-by: Jorrit Schippers Signed-off-by: Jiri Kosina

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2012-12-13T20:00:02Z

Pull trivial branch from Jiri Kosina: "Usual stuff -- comment/printk typo fixes, documentation updates, dead code elimination." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits) HOWTO: fix double words typo x86 mtrr: fix comment typo in mtrr_bp_init propagate name change to comments in kernel source doc: Update the name of profiling based on sysfs treewide: Fix typos in various drivers treewide: Fix typos in various Kconfig wireless: mwifiex: Fix typo in wireless/mwifiex driver messages: i2o: Fix typo in messages/i2o scripts/kernel-doc: check that non-void fcts describe their return value Kernel-doc: Convention: Use a "Return" section to describe return values radeon: Fix typo and copy/paste error in comments doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c various: Fix spelling of "asynchronous" in comments. Fix misspellings of "whether" in comments. eisa: Fix spelling of "asynchronous". various: Fix spelling of "registered" in comments. doc: fix quite a few typos within Documentation target: iscsi: fix comment typos in target/iscsi drivers treewide: fix typo of "suport" in various comments and Kconfig treewide: fix typo of "suppport" in various comments ...