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PCI: Introduce /sys/bus/pci/devices/.../remove

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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>
This commit is contained in:
Alex Chiang
2009-03-20 14:56:36 -06:00
committed by Jesse Barnes
parent 705b1aaa82
commit 77c27c7b49
3 changed files with 54 additions and 0 deletions
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10
Documentation/filesystems/sysfs-pci.txt
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@@ -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
----------------------------------------