[gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Mick]

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I understand that udev needs or used to need uevent_helper, but I am not clear 
if I should or should not enable this module in a new kernel I'm rolling.  Can 
you please advise:


CONFIG_UEVENT_HELPER:

The uevent helper program is forked by the kernel for
every uevent.
Before the switch to the netlink-based uevent source, this was
used to hook hotplug scripts into kernel device events. It
usually pointed to a shell script at /sbin/hotplug.
This should not be used today, because usual systems create
many events at bootup or device discovery in a very short time
frame. One forked process per event can create so many processes
that it creates a high system load, or on smaller systems
it is known to create out-of-memory situations during bootup.

Symbol: UEVENT_HELPER [=y]
Type  : boolean
Prompt: Support for uevent helper
  Location:
    -> Device Drivers
      -> Generic Driver Options
  Defined at drivers/base/Kconfig:3



Support for uevent helper (UEVENT_HELPER) [Y/n/?] (NEW) 

-- 
Regards,
Mick

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Re: [gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Neil Bothwick]

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On Fri, 24 Oct 2014 12:36:44 +0100, Mick wrote:

> I understand that udev needs or used to need uevent_helper, but I am
> not clear if I should or should not enable this module in a new kernel
> I'm rolling.  Can you please advise:
> 
> 
> CONFIG_UEVENT_HELPER:
> 
> The uevent helper program is forked by the kernel for
> every uevent.
> Before the switch to the netlink-based uevent source, this was
> used to hook hotplug scripts into kernel device events. It
> usually pointed to a shell script at /sbin/hotplug.
> This should not be used today,
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

> because usual systems create
> many events at bootup or device discovery in a very short time
> frame. One forked process per event can create so many processes
> that it creates a high system load, or on smaller systems
> it is known to create out-of-memory situations during bootup.

It's a legacy setting, introduced so you can turn off this feature.
Presumably it defaults to Y for compatibility but I've been following the
advice and running without it for some time now - on desktops and servers.

-- 
Neil Bothwick

WinErr 004: Erroneous error - Nothing is wrong

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Re: [gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Mick]

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On Friday 24 Oct 2014 12:47:14 Neil Bothwick wrote:
> On Fri, 24 Oct 2014 12:36:44 +0100, Mick wrote:
> > I understand that udev needs or used to need uevent_helper, but I am
> > not clear if I should or should not enable this module in a new kernel
> > I'm rolling.  Can you please advise:
> > 
> > 
> > CONFIG_UEVENT_HELPER:
[snip ...]

> It's a legacy setting, introduced so you can turn off this feature.
> Presumably it defaults to Y for compatibility but I've been following the
> advice and running without it for some time now - on desktops and servers.

Thanks Neil, I didn't want to end up with failing to boot.  Thanks again for a 
quick response.

-- 
Regards,
Mick

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Re: [gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Douglas J Hunley]

On Fri, Oct 24, 2014 at 7:47 AM, Neil Bothwick <neil@digimed.co.uk> wrote:
> It's a legacy setting, introduced so you can turn off this feature.
> Presumably it defaults to Y for compatibility but I've been following the
> advice and running without it for some time now - on desktops and servers.


Do you run a modular kernel or compile everything in? I do the latter,
and on 3.17.0 turning this off caused the b43 firmware for my wifi
card to not load. I'll give you that 3.17.0 has other issues, but..

-- 
Douglas J Hunley (doug.hunley@gmail.com)
Twitter: @hunleyd                                               Web:
about.me/douglas_hunley
G+: http://google.com/+DouglasHunley

Re: [gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Mick]

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On Friday 24 Oct 2014 15:13:29 Douglas J Hunley wrote:
> On Fri, Oct 24, 2014 at 7:47 AM, Neil Bothwick <neil@digimed.co.uk> wrote:
> > It's a legacy setting, introduced so you can turn off this feature.
> > Presumably it defaults to Y for compatibility but I've been following the
> > advice and running without it for some time now - on desktops and
> > servers.
> 
> Do you run a modular kernel or compile everything in? I do the latter,
> and on 3.17.0 turning this off caused the b43 firmware for my wifi
> card to not load. I'll give you that 3.17.0 has other issues, but..

Thanks for this Douglas.  I run a modular kernel with things that I only use 
occasionally compiled as modules.  All the rest is compiled in.

I am now running the 3.16.5 kernel with an ethernet cable plugged in and the 
logs look clean (other than some ACPI problems).

I just enabled the wireless adaptor and I connected to the neighboor's AP fine 
with my b43 firmware (BCM4312 chipset):

 Bluetooth: Core ver 2.19
 NET: Registered protocol family 31
 Bluetooth: HCI device and connection manager initialized
 Bluetooth: HCI socket layer initialized
 Bluetooth: L2CAP socket layer initialized
 Bluetooth: SCO socket layer initialized
 usbcore: registered new interface driver btusb
 b43-phy0: Radio hardware status changed to ENABLED
 b43-phy0: Loading firmware version 666.2 (2011-02-23 01:15:07)
 b43-phy0 debug: b2062: Using crystal tab entry 19200 kHz.
 b43-phy0 debug: Chip initialized
 b43-phy0 debug: 64-bit DMA initialized
 b43-phy0 debug: QoS disabled
 b43-phy0 debug: Wireless interface started
 b43-phy0 debug: Adding Interface type 2
 IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
 b43-phy0 ERROR: PHY transmission error
 wlan0: authenticate with 02:ac:54:e2:c8:8a
 wlan0: send auth to 02:ac:54:e2:c8:8a (try 1/3)
 wlan0: authenticated
 wlan0: associate with 02:ac:54:e2:c8:8a (try 1/3)
 wlan0: RX AssocResp from 02:ac:54:e2:c8:8a (capab=0x421 status=0 aid=1)
 wlan0: associated
 IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
 wpa_cli: interface wlan0 CONNECTED
 dhcpcd[4637]: version 6.4.7 starting

So no problem here.

-- 
Regards,
Mick

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Re: [gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Douglas J Hunley]

On Fri, Oct 24, 2014 at 10:44 AM, Mick <michaelkintzios@gmail.com> wrote:
> I just enabled the wireless adaptor and I connected to the neighboor's AP fine
> with my b43 firmware (BCM4312 chipset):


So is this a module in your kernel? It wasn't clear to me from your reply

-- 
Douglas J Hunley (doug.hunley@gmail.com)
Twitter: @hunleyd                                               Web:
about.me/douglas_hunley
G+: http://google.com/+DouglasHunley

Re: [gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Mick]

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On Monday 27 Oct 2014 13:40:32 Douglas J Hunley wrote:
> On Fri, Oct 24, 2014 at 10:44 AM, Mick <michaelkintzios@gmail.com> wrote:
> > I just enabled the wireless adaptor and I connected to the neighboor's AP
> > fine
> 
> > with my b43 firmware (BCM4312 chipset):
> So is this a module in your kernel? It wasn't clear to me from your reply

Sorry I didn't make it clear.  Yes, this is a laptop where wireless is 
optional.  Sometimes I use it and some times not.  Therefore I have it 
configured as a module.  However, it seems to be loaded whether I have 
wireless disabled or not.

$ lsmod
Module                  Size  Used by
uas                    14580  0 
ip6t_rt                 1760  3 
b43                   178521  0 
mac80211              236979  1 b43
uvcvideo               60085  0 
cfg80211              157177  2 b43,mac80211
[snip...]

-- 
Regards,
Mick

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Re: [gentoo-user] uevent_helper on kernel 3.16.5-gentoo

[Douglas J Hunley]

On Mon, Oct 27, 2014 at 11:10 AM, Mick <michaelkintzios@gmail.com> wrote:
> Sorry I didn't make it clear.  Yes, this is a laptop where wireless is
> optional.  Sometimes I use it and some times not.  Therefore I have it
> configured as a module.  However, it seems to be loaded whether I have
> wireless disabled or not.


Interesting. I'll have to poke my setup and see why it wasn't loading
for me. Thanks!

-- 
Douglas J Hunley (doug.hunley@gmail.com)
Twitter: @hunleyd                                               Web:
about.me/douglas_hunley
G+: http://google.com/+DouglasHunley