Re: Activate/deactivate kernel parameters without reboot

[Reco]

Hi.

On Fri, Mar 30, 2018 at 04:20:53PM +0200, Michael Lange wrote:
> Hi,
> 
> On Fri, 30 Mar 2018 14:40:21 +0300
> Reco  wrote:
> 
> > 
> > It won't do any good, because:
> > 
> > # ls -al /sys/module/nouveau/parameters/noaccel
> > -r 1 root root 4096 Mar 30
> > 14:37 /sys/module/nouveau/parameters/noaccel
> > 
> > Permissions of '400' in these case mean that its impossible to change
> > this module parameter via /sys (and changing them to 600 won't work
> > either). So, to answer the original question - yes, the reboot is
> > required.
> 
> I never tried, but shouldn't it be possible to do
> 
> # modprobe -r nouveau && modprobe nouveau  
> 
> in case one wants to avoid the reboot?
> Just a thought...

It should be possible, but chances are - something is using this
module. Most likely it's X (killing X should solve it) and a kernel
framebuffer (nothing to kill there).

Reboot is a must here, unless one's willing to accept the risk of kernel
panic and force unload nouveau.

Reco

Re: Activate/deactivate kernel parameters without reboot

[Michael Lange]

Hi,

On Fri, 30 Mar 2018 14:40:21 +0300
Reco  wrote:

> 
> It won't do any good, because:
> 
> # ls -al /sys/module/nouveau/parameters/noaccel
> -r 1 root root 4096 Mar 30
> 14:37 /sys/module/nouveau/parameters/noaccel
> 
> Permissions of '400' in these case mean that its impossible to change
> this module parameter via /sys (and changing them to 600 won't work
> either). So, to answer the original question - yes, the reboot is
> required.

I never tried, but shouldn't it be possible to do

# modprobe -r nouveau && modprobe nouveau  

in case one wants to avoid the reboot?
Just a thought...

Regards

Michael


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Re: Activate/deactivate kernel parameters without reboot

[tomas]

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On Fri, Mar 30, 2018 at 02:40:21PM +0300, Reco wrote:
>   Hi.

[...]

> It won't do any good, because:
> 
> # ls -al /sys/module/nouveau/parameters/noaccel
> -r 1 root root 4096 Mar 30 14:37 
> /sys/module/nouveau/parameters/noaccel

Uh-oh. Didn't see that...

> Permissions of '400' in these case mean that its impossible to change
> this module parameter via /sys (and changing them to 600 won't work
> either). So, to answer the original question - yes, the reboot is required.

Thanks for the clarification

Cheers
- -- t
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Re: Activate/deactivate kernel parameters without reboot

[Reco]

Hi.

On Fri, Mar 30, 2018 at 11:50:46AM +0200, to...@tuxteam.de wrote:
> On Fri, Mar 30, 2018 at 04:50:06AM -0300, rv riveravaldez wrote:
> > On Thu, Mar 29, 2018 at 11:28 PM, Stefan Monnier
> >  wrote:
> > >> I'm running with a 'nouveau.noaccel=1' kernel parameter added at hand
> > > [...]
> > >> Is there any way to deactivate and reactivate such a parameter without
> > >> the need to reboot?
> > >
> > > You can try and change it with
> > >
> > > # echo 0 > /sys/modules//parameters/noaccel
> > >
> > >
> > > -- Stefan
> > 
> > Hi, thanks a lot.
> > 
> > I tried it in both situations with same result.
> > 
> > Deactivate:
> > 
> > # cat /sys/module/nouveau/parameters/noaccel
> > 1
> > # echo 0 > /sys/module/nouveau/parameters/noaccel
> > bash: /sys/module/nouveau/parameters/noaccel: Permiso denegado
> > 
> > Activate:
> > 
> > # cat /sys/module/nouveau/parameters/noaccel
> > 0
> > # echo 1 > /sys/module/nouveau/parameters/noaccel
> > bash: /sys/module/nouveau/parameters/noaccel: Permiso denegado
> > 
> > 
> > 'Permiso denegado' means 'Permission denied'.
> > 
> > 
> > What else shoud/could I do?
> 
> You have to be root to change those things. Try
> 
>   sudo bash -c "echo 0 > /sys/module/nouveau/parameters/noaccel"
> 
> It will ask you for your password.

It won't do any good, because:

# ls -al /sys/module/nouveau/parameters/noaccel
-r 1 root root 4096 Mar 30 14:37 /sys/module/nouveau/parameters/noaccel

Permissions of '400' in these case mean that its impossible to change
this module parameter via /sys (and changing them to 600 won't work
either). So, to answer the original question - yes, the reboot is required.

Reco

Re: Activate/deactivate kernel parameters without reboot

[Morel Bérenger]

Hello.

Le Fri, 30 Mar 2018 04:50:06 -0300,
rv riveravaldez  a écrit :
> 'Permiso denegado' means 'Permission denied'.
> 
> 
> What else shoud/could I do?

Maybe you could try to unload the module before changing it's setup?


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Re: Activate/deactivate kernel parameters without reboot

[tomas]

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On Fri, Mar 30, 2018 at 04:50:06AM -0300, rv riveravaldez wrote:
> On Thu, Mar 29, 2018 at 11:28 PM, Stefan Monnier
>  wrote:
> >> I'm running with a 'nouveau.noaccel=1' kernel parameter added at hand
> > [...]
> >> Is there any way to deactivate and reactivate such a parameter without
> >> the need to reboot?
> >
> > You can try and change it with
> >
> > # echo 0 > /sys/modules//parameters/noaccel
> >
> >
> > -- Stefan
> 
> Hi, thanks a lot.
> 
> I tried it in both situations with same result.
> 
> Deactivate:
> 
> # cat /sys/module/nouveau/parameters/noaccel
> 1
> # echo 0 > /sys/module/nouveau/parameters/noaccel
> bash: /sys/module/nouveau/parameters/noaccel: Permiso denegado
> 
> Activate:
> 
> # cat /sys/module/nouveau/parameters/noaccel
> 0
> # echo 1 > /sys/module/nouveau/parameters/noaccel
> bash: /sys/module/nouveau/parameters/noaccel: Permiso denegado
> 
> 
> 'Permiso denegado' means 'Permission denied'.
> 
> 
> What else shoud/could I do?

You have to be root to change those things. Try

  sudo bash -c "echo 0 > /sys/module/nouveau/parameters/noaccel"

It will ask you for your password.

Cheers
- -- t
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Re: Activate/deactivate kernel parameters without reboot

[rv riveravaldez]

On Thu, Mar 29, 2018 at 11:28 PM, Stefan Monnier
 wrote:
>> I'm running with a 'nouveau.noaccel=1' kernel parameter added at hand
> [...]
>> Is there any way to deactivate and reactivate such a parameter without
>> the need to reboot?
>
> You can try and change it with
>
> # echo 0 > /sys/modules//parameters/noaccel
>
>
> -- Stefan

Hi, thanks a lot.

I tried it in both situations with same result.

Deactivate:

# cat /sys/module/nouveau/parameters/noaccel
1
# echo 0 > /sys/module/nouveau/parameters/noaccel
bash: /sys/module/nouveau/parameters/noaccel: Permiso denegado

Activate:

# cat /sys/module/nouveau/parameters/noaccel
0
# echo 1 > /sys/module/nouveau/parameters/noaccel
bash: /sys/module/nouveau/parameters/noaccel: Permiso denegado


'Permiso denegado' means 'Permission denied'.


What else shoud/could I do?


Thanks again!

Re: Activate/deactivate kernel parameters without reboot

[Stefan Monnier]

> I'm running with a 'nouveau.noaccel=1' kernel parameter added at hand
[...]
> Is there any way to deactivate and reactivate such a parameter without
> the need to reboot?

You can try and change it with

# echo 0 > /sys/modules//parameters/noaccel


-- Stefan

Activate/deactivate kernel parameters without reboot

[rv riveravaldez]

Hi,

I'm running with a 'nouveau.noaccel=1' kernel parameter added at hand
at boot (for a random freeze that appears with nouveau driver and the
NVIDIA C61 [GeForce 7025 / nForce 630a] (rev a2) GPU).

Is there any way to deactivate and reactivate such a parameter without
the need to reboot?

Thanks a lot!