Question

4

I can not find /sys/kernel/debug/vgaswitcheroo/switch

rated 0 times [ 4] [ 0] / answers: 1 / hits: 18315 / 2 Years ago, wed, february 9, 2022, 6:01:24

I have enable switcheroo in kernel config .
Why is there not /sys/kernel/debug/vgaswitcheroo/switch ?

Linux ubuntu-raid-w500 2.6.38-10-generic #46-Ubuntu SMP Tue Jun 28 15:07:17 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

My computer is Thinkpad W500 . One graphic card is ATI Mobility FireGL V5700 (512 MB). The other one is Intel Graphics Media Accelerator 4500MHD .

I am using official kernel 2.6.38-10, I do NOT customize it. I add kernel option pcie_aspm=force in GRUB_CMDLINE_LINUX_DEFAULT of /etc/default/grub

Setting modeset=1 doesn't seem to help

Here is the output of kern.log

Here is my entire bootup.

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2 Years ago

answered 2 Years ago farnic · Accepted Answer

In Ubuntu 10.10 and up, vgaswitchheroo is already enabled so you don't need extra settings. And /sys/kernel/debug is already mounted, however you need root permissions to read the contents of /sys/kernel/debug, so using sudo su should work.

If there's still no switch, run lspci | grep VGA and make sure both cards are outputted. If one is missing a BIOS setting might be the cause, so check that.

Console example:

sergio@Sergio-L:~$ ls /sys/kernel/debug/vgaswitcheroo

ls: impossível aceder a /sys/kernel/debug/vgaswitcheroo: Permissão negada

sergio@Sergio-L:~$ sudo su

[sudo] password for sergio: 

root@Sergio-L:/home/sergio#

root@Sergio-L:/home/sergio# ls /sys/kernel/debug/vgaswitcheroo/

switch

root@Sergio-L:/home/sergio#