---

yaml
---
r: 104855
b: refs/heads/master
c: 6eaaaac
h: refs/heads/master
i:
  104853: 8446e84
  104851: 006e857
  104847: ccda40b
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a1ef5adb4cad43460ebba23c5a78cf4a55bb6a5b
+refs/heads/master: 6eaaaac97433575894570a990aa27310040a8177

trunk/Documentation/ABI/testing/sysfs-dev

@@ -0,0 +1,20 @@
+What:		/sys/dev
+Date:		April 2008
+KernelVersion:	2.6.26
+Contact:	Dan Williams <dan.j.williams@intel.com>
+Description:	The /sys/dev tree provides a method to look up the sysfs
+		path for a device using the information returned from
+		stat(2).  There are two directories, 'block' and 'char',
+		beneath /sys/dev containing symbolic links with names of
+		the form "<major>:<minor>".  These links point to the
+		corresponding sysfs path for the given device.
+
+		Example:
+		$ readlink /sys/dev/block/8:32
+		../../block/sdc
+
+		Entries in /sys/dev/char and /sys/dev/block will be
+		dynamically created and destroyed as devices enter and
+		leave the system.
+
+Users:		mdadm <linux-raid@vger.kernel.org>

trunk/Documentation/DMA-attributes.txt

@@ -22,3 +22,12 @@ ready and available in memory.  The DMA of the "completion indication"
 could race with data DMA.  Mapping the memory used for completion
 indications with DMA_ATTR_WRITE_BARRIER would prevent the race.
 
+DMA_ATTR_WEAK_ORDERING
+----------------------
+
+DMA_ATTR_WEAK_ORDERING specifies that reads and writes to the mapping
+may be weakly ordered, that is that reads and writes may pass each other.
+
+Since it is optional for platforms to implement DMA_ATTR_WEAK_ORDERING,
+those that do not will simply ignore the attribute and exhibit default
+behavior.

trunk/Documentation/DocBook/uio-howto.tmpl

@@ -21,6 +21,18 @@
     </affiliation>
 </author>
 
+<copyright>
+	<year>2006-2008</year>
+	<holder>Hans-Jürgen Koch.</holder>
+</copyright>
+
+<legalnotice>
+<para>
+This documentation is Free Software licensed under the terms of the
+GPL version 2.
+</para>
+</legalnotice>
+
 <pubdate>2006-12-11</pubdate>
 
 <abstract>
@@ -29,6 +41,12 @@
 </abstract>
 
 <revhistory>
+	<revision>
+	<revnumber>0.5</revnumber>
+	<date>2008-05-22</date>
+	<authorinitials>hjk</authorinitials>
+	<revremark>Added description of write() function.</revremark>
+	</revision>
 	<revision>
 	<revnumber>0.4</revnumber>
 	<date>2007-11-26</date>
@@ -57,20 +75,9 @@
 </bookinfo>
 
 <chapter id="aboutthisdoc">
-<?dbhtml filename="about.html"?>
+<?dbhtml filename="aboutthis.html"?>
 <title>About this document</title>
 
-<sect1 id="copyright">
-<?dbhtml filename="copyright.html"?>
-<title>Copyright and License</title>
-<para>
-      Copyright (c) 2006 by Hans-Jürgen Koch.</para>
-<para>
-This documentation is Free Software licensed under the terms of the
-GPL version 2.
-</para>
-</sect1>
-
 <sect1 id="translations">
 <?dbhtml filename="translations.html"?>
 <title>Translations</title>
@@ -189,6 +196,30 @@ interested in translating it, please email me
 	represents the total interrupt count. You can use this number
 	to figure out if you missed some interrupts.
 	</para>
+	<para>
+	For some hardware that has more than one interrupt source internally,
+	but not separate IRQ mask and status registers, there might be
+	situations where userspace cannot determine what the interrupt source
+	was if the kernel handler disables them by writing to the chip's IRQ
+	register. In such a case, the kernel has to disable the IRQ completely
+	to leave the chip's register untouched. Now the userspace part can
+	determine the cause of the interrupt, but it cannot re-enable
+	interrupts. Another cornercase is chips where re-enabling interrupts
+	is a read-modify-write operation to a combined IRQ status/acknowledge
+	register. This would be racy if a new interrupt occurred
+	simultaneously.
+	</para>
+	<para>
+	To address these problems, UIO also implements a write() function. It
+	is normally not used and can be ignored for hardware that has only a
+	single interrupt source or has separate IRQ mask and status registers.
+	If you need it, however, a write to <filename>/dev/uioX</filename>
+	will call the <function>irqcontrol()</function> function implemented
+	by the driver. You have to write a 32-bit value that is usually either
+	0 or 1 to disable or enable interrupts. If a driver does not implement
+	<function>irqcontrol()</function>, <function>write()</function> will
+	return with <varname>-ENOSYS</varname>.
+	</para>
 
 	<para>
 	To handle interrupts properly, your custom kernel module can
@@ -362,6 +393,14 @@ device is actually used.
 <function>open()</function>, you will probably also want a custom
 <function>release()</function> function.
 </para></listitem>
+
+<listitem><para>
+<varname>int (*irqcontrol)(struct uio_info *info, s32 irq_on)
+</varname>: Optional. If you need to be able to enable or disable
+interrupts from userspace by writing to <filename>/dev/uioX</filename>,
+you can implement this function. The parameter <varname>irq_on</varname>
+will be 0 to disable interrupts and 1 to enable them.
+</para></listitem>
 </itemizedlist>
 
 <para>

trunk/Documentation/HOWTO

@@ -358,7 +358,7 @@ Here is a list of some of the different kernel trees available:
     - pcmcia, Dominik Brodowski <linux@dominikbrodowski.net>
 	git.kernel.org:/pub/scm/linux/kernel/git/brodo/pcmcia-2.6.git
 
-    - SCSI, James Bottomley <James.Bottomley@SteelEye.com>
+    - SCSI, James Bottomley <James.Bottomley@hansenpartnership.com>
 	git.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
 
     - x86, Ingo Molnar <mingo@elte.hu>

trunk/Documentation/filesystems/sysfs.txt

@@ -248,6 +248,7 @@ The top level sysfs directory looks like:
 block/
 bus/
 class/
+dev/
 devices/
 firmware/
 net/
@@ -274,6 +275,11 @@ fs/ contains a directory for some filesystems.  Currently each
 filesystem wanting to export attributes must create its own hierarchy
 below fs/ (see ./fuse.txt for an example).
 
+dev/ contains two directories char/ and block/. Inside these two
+directories there are symlinks named <major>:<minor>.  These symlinks
+point to the sysfs directory for the given device.  /sys/dev provides a
+quick way to lookup the sysfs interface for a device from the result of
+a stat(2) operation.
 
 More information can driver-model specific features can be found in
 Documentation/driver-model/.