lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 30 Aug 2017 22:44:00 +0200
From:   Jacek Anaszewski <>
To:     Pavel Machek <>
Cc:,,, Andrew Morton <>,, Rob Herring <>
Subject: Re: [PATCH] Documentation: small fixes for LEDs, hide notes about


On 08/29/2017 10:38 PM, Pavel Machek wrote:
> Hi!
>>> -As a specific example of this use-case, let's look at vibrate feature on
>>> -phones. Vibrate function on phones is implemented using PWM pins on SoC or
>>> -PMIC. There is a need to activate one shot timer to control the vibrate
>>> -feature, to prevent user space crashes leaving the phone in vibrate mode
>>> -permanently causing the battery to drain.
>> I'm not sure if it is a good idea to remove this description. Users will
>> still be able to use transient trigger this way. It has been around for
>> five years already and there are users which employ it in this
>> particular way [0].
> I am. Yes, people were doing that, but no, vibration motor is not a
> LED. PWM behaviour is different, for example, motor is likely to stop
> at low PWM values. We do not want people to do that.

Could you elaborate on how it can be harmful?

I really don't see any merit in removing this from documentation.

You can convince me by collecting some acks from involved people.
I'd like to especially see Rob's opinion. Adding Rob to this thread.

>> Apart from that it's the only documented kernel API for vibrate devices
> Input subsystem has force-feedback protocol, which is very often just
> vibrations. Documentation/input/ff.rst . Nokia N900 phone actually
> uses that API.

Word "vibration" doesn't appear there, so what this patch does
is remove explicit advertisement of kernel support for vibrate
devices without redirecting people to the replacement.

Best regards,
Jacek Anaszewski

Powered by blists - more mailing lists