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authorAlex Chiang <achiang@hp.com>2009-03-20 14:56:36 -0600
committerJesse Barnes <jbarnes@virtuousgeek.org>2009-03-20 14:58:48 -0700
commit77c27c7b49d69d45ccb94e481653f024f1ac6650 (patch)
tree8f2e7a6f3971e3630ad1d219bee1c673597158fe /Documentation/filesystems
parent705b1aaa823e800490f157cd9366ad8cff385f5f (diff)
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PCI: Introduce /sys/bus/pci/devices/.../remove
This patch adds an attribute named "remove" to a PCI device's sysfs directory. Writing a non-zero value to this attribute will remove the PCI device and any children of it. Trent Piepho wrote the original implementation and documentation. Thanks to Vegard Nossum for testing under kmemcheck and finding locking issues with the sysfs interface. Cc: Trent Piepho <xyzzy@speakeasy.org> Tested-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/sysfs-pci.txt10
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 9f8740c..26e4b8b 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -12,6 +12,7 @@ that support it. For example, a given bus might look like this:
| |-- enable
| |-- irq
| |-- local_cpus
+ | |-- remove
| |-- resource
| |-- resource0
| |-- resource1
@@ -36,6 +37,7 @@ files, each with their own function.
enable Whether the device is enabled (ascii, rw)
irq IRQ number (ascii, ro)
local_cpus nearby CPU mask (cpumask, ro)
+ remove remove device from kernel's list (ascii, wo)
resource PCI resource host addresses (ascii, ro)
resource0..N PCI resource N, if present (binary, mmap)
resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap)
@@ -46,6 +48,7 @@ files, each with their own function.
ro - read only file
rw - file is readable and writable
+ wo - write only file
mmap - file is mmapable
ascii - file contains ascii text
binary - file contains binary data
@@ -73,6 +76,13 @@ that the device must be enabled for a rom read to return data succesfully.
In the event a driver is not bound to the device, it can be enabled using the
'enable' file, documented above.
+The 'remove' file is used to remove the PCI device, by writing a non-zero
+integer to the file. This does not involve any kind of hot-plug functionality,
+e.g. powering off the device. The device is removed from the kernel's list of
+PCI devices, the sysfs directory for it is removed, and the device will be
+removed from any drivers attached to it. Removal of PCI root buses is
+disallowed.
+
Accessing legacy resources through sysfs
----------------------------------------