1
Commit Graph

168333 Commits

Author SHA1 Message Date
Troy Kisky
1e224f322b ASoC: DaVinci: pcm, fix underrun by using sram
Fix underruns by using dma to copy 1st to sram
in a ping/pong buffer style and then copying from
the sram to the ASP. This also has the advantage
of tolerating very long interrupt latency on dma
completion.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-19 10:48:08 +00:00
Troy Kisky
1587ea3157 ASoC: DaVinci: pcm, rename variables in prep for ping/pong
Rename variable master_lch to asp_channel
Rename variable slave_lch to asp_link[0]
Rename local variables:
	lch to link
	count to asp_count
	src to asp_src
	dst to asp_dst

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-19 10:47:56 +00:00
Troy Kisky
0d6c977429 ASoC: DaVinci: i2s, reduce underruns by combining into 1 element
Allow the left and right 16 bit samples to be shifted out as 1
32 bit sample.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-19 10:47:38 +00:00
Mark Brown
41b51dd47e Merge branch 'for-2.6.32' into for-2.6.33 2009-11-18 13:54:51 +00:00
Troy Kisky
bab0212467 ASoC: tlv320aic23 fix rate selection
Fix the ordering of sr_valid_mask array.
The lower bit of the index represents USB
not bosr.

Reported-by: Anuj Aggarwal <anuj.aggarwal@ti.com>
Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:46:40 +00:00
Grazvydas Ignotas
f3dd70414c ASoC: OMAP3 Pandora: update for TWL4030 codec changes
A while ago TWL4030 had it's playback stream name changed, but
pandora needs it for it's playback path. Update to correct stream
name so that playback works again.

Also mark VIBRA output as not connected.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:46:40 +00:00
Anuj Aggarwal
bd6ddcb41d ASoC: Modifying the license string GPLv2 for OMAP3 EVM
Correcting the license string from GPLv2 -> GPL v2.
Found the problem while building OMAP3 ASoC driver as
module.

Signed-off-by: Anuj Aggarwal <anuj.aggarwal@ti.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:46:39 +00:00
Mark Brown
1452556beb Merge branch 'topic/asoc' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6 into for-2.6.33 2009-11-18 13:42:05 +00:00
Troy Kisky
57512c6432 ASoC: DaVinci: remove requirement that dma_params is 1st in structure
Remove requirement that dma_params is 1st in the structures
davinci_audio_dev and davinci_mcbsp_dev.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:35:06 +00:00
Jassi Brar
357a1db94e ASoC: Added the CPU driver for PCM controllers
Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:35:05 +00:00
Jassi Brar
acf1aef9ec ARM: S3C64XX: Defined PCM controller platform devices
Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:35:05 +00:00
Jassi Brar
07e74c0ac8 ARM: S3C64XX: Added platform data header
Many SoCs have their I2S pins MUXed with other functions. So we need
to pass a callback for driver to configure the pins appropriately.
Hence, the need of platform data and this header.

As and when needed new callbacks and structure pointers maybe added to this
header.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:35:04 +00:00
Jassi Brar
93f85130e1 ARM: S3C64XX: Define PCM Controller base registers
Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:35:04 +00:00
Jassi Brar
d3ff5a3e61 ASoC: Rename 's3c24xx-pcm' driver to 's3c-dma'
Making room for namespace for the PCM Controller driver
the platform driver(s3c24xx-pcm) has been renamed to SoC
agnostic name 's3c-dma'.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:35:03 +00:00
Jassi Brar
faa31776e4 ASoC: Rename s3c24xx_pcm prefix to s3c_dma
The s3c24xx_pcm prefix for the soc_platform is inappropriate when
some Samsung SoCs have PCM controllers which will eventually have
drivers and hence namespace ambiguities.

To resolve naming ambiguities in future the following have been
renamed in order
1) s3c24xx_pcm_dma_params -> s3c_dma_params
2) s3c24xx_pcm_preallocate_dma_buffer -> s3c_preallocate_dma_buffer
3) s3c24xx_pcm_dmamask -> s3c_dma_mask
4) s3c24xx_pcm_XXX -> s3c_dma_XXX

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-18 13:35:03 +00:00
Marin Mitov
f9ede4eca0 ASoC: Use DMA_BIT_MASK(32) instead of deprecated DMA_32BIT_MASK
Signed-off-by: Marin Mitov <mitov@issp.bas.bg>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2009-11-17 09:04:06 +01:00
Mike Rapoport
8df89bc35c ASoC: OMAP: enable Overo driver for CM-T35
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Acked-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-16 16:02:03 +00:00
Mark Brown
0a3f5e35aa ASoC: Remove redundant snd_soc_dapm_new_widgets() calls
The DAPM widgets are now insntantiated by the core when creating the card
so there is no need for the individual CODEC drivers to do so.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-12 23:15:08 +00:00
Joonyoung Shim
c871a05315 ASoC: Add jack_status_check callback function for GPIO jacks
The jack_status_check callback function is the interface to check the
status of the jack. Some target provides the method to distinguish what
is the jack inserted - headphone jack, microphone jack, tvout jack, etc,
so we can implement it using the jack_status_check function.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-12 16:45:53 +00:00
Barry Song
f773205300 ASoC: move setting ac97 platformdata earlier than ac97 read/write
While probing, AC97 codec drivers and soc-core generically execute the
following sequence:
snd_soc_new_ac97_codec -> snd_soc_new_pcms -> reset ac-link/read AC97 ID
to detect ->...  -> set platform_data to ac97 by soc-core

commit 474828a40f adds platform_data to
snd_ac97 instance. But ac97 platform data hasn't given to snd_ac97
before actual ac97 operations. Then while ac97_read access platform_data
of snd_ac97 for detecting, NULL pointer oops will fire. That means old
platform_data patch doesn't work in real-life cases.

This patch moves the operation of setting ac97 platform_data earlier
than ac97 reading/writing operations. Then it makes platform_data of
AC97 become practically useful.

Signed-off-by: Barry Song <21cnbao@gmail.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-12 16:45:52 +00:00
Jassi Brar
ba2b87f5a9 ASoC: Fixed arguments passed to SMDK64xx set_pll
Corrected the order of 'source' and 'pll_id' arguments.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-12 16:45:51 +00:00
Mark Brown
7aae816dae ASoC: Add bit clock rate calculator utility functions
Many devices need to calculate the bit clock rate desired to
work out the clock configuration required for the device.
Provide utility functions to do this using both hw_params
structures and raw numbers.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-11-12 16:45:48 +00:00
Grant Likely
a68cc8daeb ASoC: mpc5200: remove duplicate identical IRQ handler
The TX and RX irq handlers are identical.  Merge them

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-10 13:02:01 +00:00
Peter Ujfalusi
68d019553b ASoC: TWL4030: Do not modify the APLL_CTL register
APLL_CTL register is configured by the twl4030-codec MFD
driver.
Remove code, which makes changes in the APLL_CTL register,
and replace those with checks against the configured
audio_mclk configuration done in the MFD driver.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-10 12:08:15 +00:00
Mark Brown
0969afcc44 Merge branch 'twl4030-mfd' into for-2.6.33 2009-11-10 12:08:12 +00:00
Peter Ujfalusi
f9b4639e04 MFD: twl4030-codec: APLL_INFREQ handling in the MFD driver
Configure the APLL_INFREQ field in the APLL_CTL register
based on the platform data.
Provide also a function for childs to query the audio_mclk
frequency.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-10 12:07:23 +00:00
Peter Ujfalusi
953e2f3d27 OMAP: Configure audio_mclk for twl4030-codec MFD
audio_mclk value is going to be handled by the
twl4030-codec MFD driver, configure the correct
value for boards, which is using the twl4030 audio.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-10 12:07:23 +00:00
Peter Ujfalusi
cfd5324e69 MFD: TWL4030: Add audio_mclk to the codec platform data
Add audio_mclk to the platform data struct for the
twl4030-codec MFD driver.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-10 12:07:23 +00:00
Graeme Gregory
5f63ef9909 ASoC: omap-mcbsp - add support for upto 16 channels.
This patch increases the number of supported audio channels from 4
to 16 and has been sponsored by Shotspotter Inc. It also fixes a
FSYNC rate calculation bug when McBSP is FSYNC master.

Signed-off-by: Graeme Gregory <gg@slimlogic.co.uk>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
Acked-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-10 11:58:21 +00:00
Jarkko Nikula
9e5d86fe6a ASoC: Pandora: Pass SRG input clock frequency to the OMAP McBSP DAI
Upcoming change to omap-mcbsp.c require that machine drivers using OMAP
as a DAI master to pass sample rate generator input clock frequency to
the omap-mcbsp.c DAI driver.

Pandora is using 256*Fs output from the TWL4030 codec as an input clock to
the McBSP sample rate generator.

Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>
Tested-by: Grazvydas Ignotas <notasas@gmail.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-09 13:18:34 +00:00
Grant Likely
c939e5c821 ASoC/mpc5200: fix enable/disable of AC97 slots
The MPC5200 AC97 driver is disabling the slots when a stop
trigger is received, but not reenabling them if the stream
is started again without processing the hw_params again.

This patch fixes the problem by caching the slot enable bit
settings calculated at hw_params time so that they can be
reapplied every time the start trigger is received.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-07 12:40:09 +00:00
Grant Likely
1d8222e8df ASoC/mpc5200: add to_psc_dma_stream() helper
Move the resolving of the psc_dma_stream pointer to a helper function
to reduce duplicate code

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-07 12:40:09 +00:00
Grant Likely
c487827475 ASoC/mpc5200: Improve printk debug output for trigger
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-07 12:40:08 +00:00
Grant Likely
d56b6eb6df ASoC/mpc5200: get rid of the appl_ptr tracking nonsense
Sound drivers PCM DMA is supposed to free-run until told to stop
by the trigger callback.  The current code tries to track appl_ptr,
to avoid stale buffer data getting played out at the end of the
data stream.  Unfortunately it also results in race conditions
which can cause the audio to stall.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-07 12:40:08 +00:00
Grant Likely
8f159d720b ASoC/mpc5200: Track DMA position by period number instead of bytes
All DMA blocks are lined up to period boundaries, but the DMA
handling code tracks bytes instead.  This patch reworks the code
to track the period index into the DMA buffer instead of the
physical address pointer.  Doing so makes the code simpler and
easier to understand.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-07 12:40:08 +00:00
Takashi Iwai
4cae37fa98 ASoC: Remove dead code and labels
Remove the dead code and labels "card_err" in the error paths of
some codec drivers.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2009-11-07 10:18:22 +01:00
Mark Brown
330f28f691 Merge branch 'for-2.6.32' into for-2.6.33 2009-11-06 15:46:18 +00:00
Jassi Brar
6fc786d503 ASoC: S3C64XX I2S: Enable audio-bus clock
Added the missing clk_enable after acquiring the 'audio-bus' clock.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-06 13:54:26 +00:00
Janusz Krzysztofik
4d187fb830 ASoC: OMAP: Don't try to set unsupported OMAP_DMA_DATA_BURST_16 on OMAP1
After DMA burst mode has been introduced in sound/soc/omap/omap-pcm.c,
omap_pcm_prepare() unconditionally calls:

        omap_set_dma_src_burst_mode(prtd->dma_ch, OMAP_DMA_DATA_BURST_16);
        omap_set_dma_dest_burst_mode(prtd->dma_ch, OMAP_DMA_DATA_BURST_16);

Current implementation of those two functions found in
arch/arm/plat-ompa/dma.c doesn't support OMAP_DMA_DATA_BURST_16 on OMAP1 at
all, so they both end with BUG() on that machine. That results in
ASoC being completely unusable, at least on my OMAP5910 based Amstrad Delta.

The patch corrects the problem by not calling those two functions when run on
OMAP1 class based machines.

Created against linux-2.6.32-rc5.
Tested on Amstrad Delta.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-06 13:54:26 +00:00
Mark Brown
fe3e78e073 ASoC: Factor out snd_soc_init_card()
snd_soc_init_card() is always called as the last part of the CODEC probe
function so we can factor it out into the core card setup rather than
have each CODEC replicate the code to do the initialiastation. This will
be required to support multiple CODECs per card.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-03 22:14:43 +00:00
Mark Brown
2624d5fa67 ASoC: Move sysfs and debugfs functions to head of soc-core.c
A fairly hefty change in diff terms but no actual code changes, will be
used by the next commit.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-03 22:14:41 +00:00
Mark Brown
529697c546 ASoC: Staticise wm8727 driver structure
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-11-03 22:14:31 +00:00
Linus Torvalds
b419148e56 Linux 2.6.32-rc6 2009-11-03 11:37:49 -08:00
Linus Torvalds
79051db9ae Merge branch 'for-linus' of git://github.com/at91linux/linux-2.6-at91
* 'for-linus' of git://github.com/at91linux/linux-2.6-at91:
  at91: at91sam9g45 family: identify several chip versions
  avr32: add two new at91 to cpu.h definition
2009-11-03 11:15:25 -08:00
Nicolas Ferre
d8951adeba at91: at91sam9g45 family: identify several chip versions
cpu_is_xxx() macros are identifying generic at91sam9g45 chip. This patch adds
the capacity to differentiate Engineering Samples and final lots through the
inclusion of  at91_cpu_fully_identify() and the related chip IDs with chip
version field preserved.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
2009-11-03 18:42:31 +01:00
Nicolas Ferre
2f5d46d2f6 avr32: add two new at91 to cpu.h definition
Somme common drivers will need those at91 cpu_is_xxx() definitions. As
at91sam9g10 and at91sam9g45 are on the way to linus' tree, here is the patch
that adds those chips to cpu.h in AVR32 architecture.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
2009-11-03 18:36:35 +01:00
Linus Torvalds
9ddfd92909 Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (38 commits)
  MIPS: O32: Fix ppoll
  MIPS: Oprofile: Rename cpu_type from godson2 to loongson2
  MIPS: Alchemy: Fix hang with high-frequency edge interrupts
  MIPS: TXx9: Fix spi-baseclk value
  MIPS: bcm63xx: Set the correct BCM3302 CPU name
  MIPS: Loongson 2: Set cpu_has_dc_aliases and cpu_icache_snoops_remote_store
  MIPS: Avoid potential hazard on Context register
  MIPS: Octeon: Use lockless interrupt controller operations when possible.
  MIPS: Octeon: Use write_{un,}lock_irq{restore,save} to set irq affinity
  MIPS: Set S-cache linesize to 64-bytes for MTI's S-cache
  MIPS: SMTC: Avoid queing multiple reschedule IPIs
  MIPS: GCMP: Avoid accessing registers when they are not present
  MIPS: GIC: Random fixes and enhancements.
  MIPS: CMP: Fix memory barriers for correct operation of amon_cpu_start
  MIPS: Fix abs.[sd] and neg.[sd] emulation for NaN operands
  MIPS: SPRAM: Clean up support code a little
  MIPS: 1004K: Enable SPRAM support.
  MIPS: Malta: Enable PCI 2.1 compatibility in PIIX4
  MIPS: Kconfig: Fix duplicate default value for MIPS_L1_CACHE_SHIFT.
  MIPS: MTI: Fix accesses to device registers on MIPS boards
  ...
2009-11-03 08:09:57 -08:00
Linus Torvalds
38dc63459f Merge branch 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  PM: Remove some debug messages producing too much noise
  PM: Fix warning on suspend errors
  PM / Hibernate: Add newline to load_image() fail path
  PM / Hibernate: Fix error handling in save_image()
  PM / Hibernate: Fix blkdev refleaks
  PM / yenta: Split resume into early and late parts (rev. 4)
2009-11-03 07:52:57 -08:00
Ian Campbell
1d51075094 Correct nr_processes() when CPUs have been unplugged
nr_processes() returns the sum of the per cpu counter process_counts for
all online CPUs. This counter is incremented for the current CPU on
fork() and decremented for the current CPU on exit(). Since a process
does not necessarily fork and exit on the same CPU the process_count for
an individual CPU can be either positive or negative and effectively has
no meaning in isolation.

Therefore calculating the sum of process_counts over only the online
CPUs omits the processes which were started or stopped on any CPU which
has since been unplugged. Only the sum of process_counts across all
possible CPUs has meaning.

The only caller of nr_processes() is proc_root_getattr() which
calculates the number of links to /proc as
        stat->nlink = proc_root.nlink + nr_processes();

You don't have to be all that unlucky for the nr_processes() to return a
negative value leading to a negative number of links (or rather, an
apparently enormous number of links). If this happens then you can get
failures where things like "ls /proc" start to fail because they got an
-EOVERFLOW from some stat() call.

Example with some debugging inserted to show what goes on:
        # ps haux|wc -l
        nr_processes: CPU0:     90
        nr_processes: CPU1:     1030
        nr_processes: CPU2:     -900
        nr_processes: CPU3:     -136
        nr_processes: TOTAL:    84
        proc_root_getattr. nlink 12 + nr_processes() 84 = 96
        84
        # echo 0 >/sys/devices/system/cpu/cpu1/online
        # ps haux|wc -l
        nr_processes: CPU0:     85
        nr_processes: CPU2:     -901
        nr_processes: CPU3:     -137
        nr_processes: TOTAL:    -953
        proc_root_getattr. nlink 12 + nr_processes() -953 = -941
        75
        # stat /proc/
        nr_processes: CPU0:     84
        nr_processes: CPU2:     -901
        nr_processes: CPU3:     -137
        nr_processes: TOTAL:    -954
        proc_root_getattr. nlink 12 + nr_processes() -954 = -942
          File: `/proc/'
          Size: 0               Blocks: 0          IO Block: 1024   directory
        Device: 3h/3d   Inode: 1           Links: 4294966354
        Access: (0555/dr-xr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
        Access: 2009-11-03 09:06:55.000000000 +0000
        Modify: 2009-11-03 09:06:55.000000000 +0000
        Change: 2009-11-03 09:06:55.000000000 +0000

I'm not 100% convinced that the per_cpu regions remain valid for offline
CPUs, although my testing suggests that they do. If not then I think the
correct solution would be to aggregate the process_count for a given CPU
into a global base value in cpu_down().

This bug appears to pre-date the transition to git and it looks like it
may even have been present in linux-2.6.0-test7-bk3 since it looks like
the code Rusty patched in http://lwn.net/Articles/64773/ was already
wrong.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-03 07:52:39 -08:00
Linus Torvalds
1c211849d8 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: gpio-keys - use IRQF_SHARED
  Input: winbond-cir - select LEDS_TRIGGERS
  Input: i8042 - try to get stable CTR value when initializing
  Input: atkbd - add a quirk for OQO 01+ multimedia keys
2009-11-03 07:46:17 -08:00