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r: 198988
b: refs/heads/master
c: e2e2400
h: refs/heads/master
v: v3
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Linus Torvalds committed May 27, 2010
1 parent 8be475b commit fb3f6ec
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: f9e8894ae5157796dd69249c56062042d02a431d
refs/heads/master: e2e2400bd4faee24d11872134b7ae5bd363749c0
20 changes: 20 additions & 0 deletions trunk/Documentation/ABI/testing/sysfs-class-power
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What: /sys/class/power/ds2760-battery.*/charge_now
Date: May 2010
KernelVersion: 2.6.35
Contact: Daniel Mack <daniel@caiaq.de>
Description:
This file is writeable and can be used to set the current
coloumb counter value inside the battery monitor chip. This
is needed for unavoidable corrections of aging batteries.
A userspace daemon can monitor the battery charging logic
and once the counter drops out of considerable bounds, take
appropriate action.

What: /sys/class/power/ds2760-battery.*/charge_full
Date: May 2010
KernelVersion: 2.6.35
Contact: Daniel Mack <daniel@caiaq.de>
Description:
This file is writeable and can be used to set the assumed
battery 'full level'. As batteries age, this value has to be
amended over time.
7 changes: 7 additions & 0 deletions trunk/Documentation/ABI/testing/sysfs-devices-node
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What: /sys/devices/system/node/nodeX/compact
Date: February 2010
Contact: Mel Gorman <mel@csn.ul.ie>
Description:
When this file is written to, all memory within that node
will be compacted. When it completes, memory will be freed
into blocks which have as many contiguous pages as possible
85 changes: 49 additions & 36 deletions trunk/Documentation/DMA-API-HOWTO.txt
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Expand Up @@ -639,6 +639,36 @@ is planned to completely remove virt_to_bus() and bus_to_virt() as
they are entirely deprecated. Some ports already do not provide these
as it is impossible to correctly support them.

Handling Errors

DMA address space is limited on some architectures and an allocation
failure can be determined by:

- checking if dma_alloc_coherent returns NULL or dma_map_sg returns 0

- checking the returned dma_addr_t of dma_map_single and dma_map_page
by using dma_mapping_error():

dma_addr_t dma_handle;

dma_handle = dma_map_single(dev, addr, size, direction);
if (dma_mapping_error(dev, dma_handle)) {
/*
* reduce current DMA mapping usage,
* delay and try again later or
* reset driver.
*/
}

Networking drivers must call dev_kfree_skb to free the socket buffer
and return NETDEV_TX_OK if the DMA mapping fails on the transmit hook
(ndo_start_xmit). This means that the socket buffer is just dropped in
the failure case.

SCSI drivers must return SCSI_MLQUEUE_HOST_BUSY if the DMA mapping
fails in the queuecommand hook. This means that the SCSI subsystem
passes the command to the driver again later.

Optimizing Unmap State Space Consumption

On many platforms, dma_unmap_{single,page}() is simply a nop.
Expand Down Expand Up @@ -703,42 +733,25 @@ to "Closing".

1) Struct scatterlist requirements.

Struct scatterlist must contain, at a minimum, the following
members:

struct page *page;
unsigned int offset;
unsigned int length;

The base address is specified by a "page+offset" pair.

Previous versions of struct scatterlist contained a "void *address"
field that was sometimes used instead of page+offset. As of Linux
2.5., page+offset is always used, and the "address" field has been
deleted.

2) More to come...

Handling Errors

DMA address space is limited on some architectures and an allocation
failure can be determined by:

- checking if dma_alloc_coherent returns NULL or dma_map_sg returns 0

- checking the returned dma_addr_t of dma_map_single and dma_map_page
by using dma_mapping_error():

dma_addr_t dma_handle;

dma_handle = dma_map_single(dev, addr, size, direction);
if (dma_mapping_error(dev, dma_handle)) {
/*
* reduce current DMA mapping usage,
* delay and try again later or
* reset driver.
*/
}
Don't invent the architecture specific struct scatterlist; just use
<asm-generic/scatterlist.h>. You need to enable
CONFIG_NEED_SG_DMA_LENGTH if the architecture supports IOMMUs
(including software IOMMU).

2) ARCH_KMALLOC_MINALIGN

Architectures must ensure that kmalloc'ed buffer is
DMA-safe. Drivers and subsystems depend on it. If an architecture
isn't fully DMA-coherent (i.e. hardware doesn't ensure that data in
the CPU cache is identical to data in main memory),
ARCH_KMALLOC_MINALIGN must be set so that the memory allocator
makes sure that kmalloc'ed buffer doesn't share a cache line with
the others. See arch/arm/include/asm/cache.h as an example.

Note that ARCH_KMALLOC_MINALIGN is about DMA memory alignment
constraints. You don't need to worry about the architecture data
alignment constraints (e.g. the alignment constraints about 64-bit
objects).

Closing

Expand Down
2 changes: 1 addition & 1 deletion trunk/Documentation/DocBook/mtdnand.tmpl
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Expand Up @@ -269,7 +269,7 @@ static void board_hwcontrol(struct mtd_info *mtd, int cmd)
information about the device.
</para>
<programlisting>
int __init board_init (void)
static int __init board_init (void)
{
struct nand_chip *this;
int err = 0;
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12 changes: 12 additions & 0 deletions trunk/Documentation/SubmitChecklist
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Expand Up @@ -18,6 +18,8 @@ kernel patches.

2b: Passes allnoconfig, allmodconfig

2c: Builds successfully when using O=builddir

3: Builds on multiple CPU architectures by using local cross-compile tools
or some other build farm.

Expand Down Expand Up @@ -95,3 +97,13 @@ kernel patches.

25: If any ioctl's are added by the patch, then also update
Documentation/ioctl/ioctl-number.txt.

26: If your modified source code depends on or uses any of the kernel
APIs or features that are related to the following kconfig symbols,
then test multiple builds with the related kconfig symbols disabled
and/or =m (if that option is available) [not all of these at the
same time, just various/random combinations of them]:

CONFIG_SMP, CONFIG_SYSFS, CONFIG_PROC_FS, CONFIG_INPUT, CONFIG_PCI,
CONFIG_BLOCK, CONFIG_PM, CONFIG_HOTPLUG, CONFIG_MAGIC_SYSRQ,
CONFIG_NET, CONFIG_INET=n (but latter with CONFIG_NET=y)
5 changes: 5 additions & 0 deletions trunk/Documentation/SubmittingDrivers
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Expand Up @@ -130,6 +130,8 @@ Linux kernel master tree:
ftp.??.kernel.org:/pub/linux/kernel/...
?? == your country code, such as "us", "uk", "fr", etc.

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git

Linux kernel mailing list:
linux-kernel@vger.kernel.org
[mail majordomo@vger.kernel.org to subscribe]
Expand Down Expand Up @@ -160,3 +162,6 @@ How to NOT write kernel driver by Arjan van de Ven:

Kernel Janitor:
http://janitor.kernelnewbies.org/

GIT, Fast Version Control System:
http://git-scm.com/
2 changes: 1 addition & 1 deletion trunk/Documentation/cgroups/cgroups.txt
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Expand Up @@ -339,7 +339,7 @@ To mount a cgroup hierarchy with all available subsystems, type:
The "xxx" is not interpreted by the cgroup code, but will appear in
/proc/mounts so may be any useful identifying string that you like.

To mount a cgroup hierarchy with just the cpuset and numtasks
To mount a cgroup hierarchy with just the cpuset and memory
subsystems, type:
# mount -t cgroup -o cpuset,memory hier1 /dev/cgroup

Expand Down
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