Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / Documentation / filesystems / sysfs-pci.txt

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index e97d024..7ba2baa 100644 (file)
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -1,4 +1,5 @@
 Accessing PCI device resources through sysfs
+--------------------------------------------
 
 sysfs, usually mounted at /sys, provides access to PCI resources on platforms
 that support it.  For example, a given bus might look like this:
@@ -7,7 +8,6 @@ that support it.  For example, a given bus might look like this:
      |-- 0000:17:00.0
      |   |-- class
      |   |-- config
-     |   |-- detach_state
      |   |-- device
      |   |-- irq
      |   |-- local_cpus
@@ -19,7 +19,7 @@ that support it.  For example, a given bus might look like this:
      |   |-- subsystem_device
      |   |-- subsystem_vendor
      |   `-- vendor
-     `-- detach_state
+     `-- ...
 
 The topmost element describes the PCI domain and bus number.  In this case,
 the domain number is 0000 and the bus number is 17 (both values are in hex).
@@ -31,7 +31,6 @@ files, each with their own function.
        ----               --------
        class              PCI class (ascii, ro)
        config             PCI config space (binary, rw)
-       detach_state       connection status (bool, rw)
        device             PCI device (ascii, ro)
        irq                IRQ number (ascii, ro)
        local_cpus         nearby CPU mask (cpumask, ro)
@@ -49,14 +48,21 @@ files, each with their own function.
   binary - file contains binary data
   cpumask - file contains a cpumask type
 
-The read only files are informational, writes to them will be ignored.
-Writable files can be used to perform actions on the device (e.g. changing
-config space, detaching a device).  mmapable files are available via an
-mmap of the file at offset 0 and can be used to do actual device programming
-from userspace.  Note that some platforms don't support mmapping of certain
-resources, so be sure to check the return value from any attempted mmap.
+The read only files are informational, writes to them will be ignored, with
+the exception of the 'rom' file.  Writable files can be used to perform
+actions on the device (e.g. changing config space, detaching a device).
+mmapable files are available via an mmap of the file at offset 0 and can be
+used to do actual device programming from userspace.  Note that some platforms
+don't support mmapping of certain resources, so be sure to check the return
+value from any attempted mmap.
+
+The 'rom' file is special in that it provides read-only access to the device's
+ROM file, if available.  It's disabled by default, however, so applications
+should write the string "1" to the file to enable it before attempting a read
+call, and disable it following the access by writing "0" to the file.
 
 Accessing legacy resources through sysfs
+----------------------------------------
 
 Legacy I/O port and ISA memory resources are also provided in sysfs if the
 underlying platform supports them.  They're located in the PCI class heirarchy,
@@ -77,6 +83,7 @@ simply dereference the returned pointer (after checking for errors of course)
 to access legacy memory space.
 
 Supporting PCI access on new platforms
+--------------------------------------
 
 In order to support PCI resource mapping as described above, Linux platform
 code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function.
@@ -85,4 +92,4 @@ useful return codes should be provided.
 
 Legacy resources are protected by the HAVE_PCI_LEGACY define.  Platforms
 wishing to support legacy functionality should define it and provide
-pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.
\ No newline at end of file
+pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.