CODEWITHSUNDEEP
linuxlinux-kernel
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Reputation: 6474

writing in /sys/bus/pci/... fails

Attempt to run the following command with root privilege on kernel 2.6.35 results in error:

% echo 0000:00:03.0 > /sys/bus/pci/drivers/foo/bind
-bash: echo: write error: No such device

UPDATE The device does exist in /sys/bus/pci/devices/ the output of lspci is as follows:

% lspci -v -s 0000:00:03.0
00:03.0 Ethernet controller: Intel Corporation 82540EM Gigabit Ethernet Controller (rev 02)
    Subsystem: Intel Corporation PRO/1000 MT Desktop Adapter
    Flags: bus master, 66MHz, medium devsel, latency 64, IRQ 10
    Memory at f0000000 (32-bit, non-prefetchable) [size=128K]
    I/O ports at d010 [size=8]
    Capabilities: <access denied>
    Kernel driver in use: e1000

Upvotes: 1

Views: 13014

Answers (1)

Mark
Mark

Reputation: 6474

I think I resolved the issue. It appears that the driver requires to unbind device at first.

It also appears that the shell processes redirection (echo .. > /sys/bus/..) with user permission, and 'sudo' handles only the command, i.e. 'echo' but not the whole command line that follows it, therefore it has to be executed this way:

% sudo sh -c "echo 0000:00:03.0 > /sys/bus/pci/drivers/foo/unbind"
% sudo sh -c "echo 0000:00:03.0 > /sys/bus/pci/drivers/foo_new/bind"

Upvotes: 3

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