linux-kernel - RE: [PATCH v2 1/2] platform/x86: dell-privacy: Add support for Dell hardware privacy

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Date:   Fri, 8 Jan 2021 17:04:48 +0000
From:   "Yuan, Perry" <Perry.Yuan@...l.com>
To:     Barnabás Pocze <pobrn@...tonmail.com>,
        Hans de Goede <hdegoede@...hat.com>
CC:     "mgross@...ux.intel.com" <mgross@...ux.intel.com>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Limonciello, Mario" <Mario.Limonciello@...l.com>,
        "Wang, David D" <David.D.Wang@...l.com>,
        "Zhang, Zorro" <Zorro.Zhang@...l.com>
Subject: RE: [PATCH v2 1/2] platform/x86: dell-privacy: Add support for Dell
 hardware privacy

Dell Customer Communication - Confidential

> -----Original Message-----
> From: Barnabás Pőcze <pobrn@...tonmail.com>
> Sent: 2021年1月8日 0:04
> To: Hans de Goede
> Cc: Yuan, Perry; mgross@...ux.intel.com; platform-driver-
> x86@...r.kernel.org; linux-kernel@...r.kernel.org; Limonciello, Mario
> Subject: Re: [PATCH v2 1/2] platform/x86: dell-privacy: Add support for Dell
> hardware privacy
> 
> 
> [EXTERNAL EMAIL]
> 
> Hi
> 
> 
> 2021. január 7., csütörtök 0:43 keltezéssel, Hans de Goede írta:
> 
> > Hi Perry,
> >
> > On 12/28/20 2:28 PM, Perry Yuan wrote:
> >
> > > From: Perry Yuan perry_yuan@...l.com add support for dell privacy
> > > driver for the dell units equipped hardware privacy design, which
> > > protect users privacy of audio and camera from hardware level. once
> > > the audio or camera privacy mode enabled, any applications will not
> > > get any audio or video stream.
> > > when user pressed ctrl+F4 hotkey, audio privacy mode will be
> > > enabled,Micmute led will be also changed accordingly.
> > > The micmute led is fully controlled by hardware & EC.
> > > and camera mute hotkey is ctrl+F9.currently design only emmit
> > > SW_CAMERA_LENS_COVER event while the camera LENS shutter will be
> > > changed by EC & HW control.
> > > *The flow is like this:
> > >
> > > 1.  User presses key. HW does stuff with this key (timeout is
> > > started) 2.  Event is emitted from FW 3.  Event received by
> > > dell-privacy 4.  KEY_MICMUTE emitted from dell-privacy 5.  Userland
> > > picks up key and modifies kcontrol for SW mute 6.  Codec kernel
> > > driver catches and calls ledtrig_audio_set, like this:
> > >     ledtrig_audio_set(LED_AUDIO_MICMUTE,
> > >     rt715->micmute_led ? LED_ON :LED_OFF);
> > >
> > > 7.  If "LED" is set to on dell-privacy notifies ec,
> > >     and timeout is cancelled,HW mic mute activated.
> > >
> > >
> > > Signed-off-by: Perry Yuan perry_yuan@...l.com
> > > Signed-off-by: Limonciello Mario mario_limonciello@...l.com
> >
> > Thank you for your patch, please send a new version addressing
> > Barnabás' review comment and including the second patch of the series.
> > [...]
> 
> I think first something needs to be figured out regarding the integration with
> the rest of the Dell modules. I feel that list is not a desirable way to do it.
> 
> 
> Regards,
> Barnabás Pőcze

Hi Barnabás, Hans.
Thanks for your review and comments.
Before I send V3, I would explain some detail why we have two files for the dell privacy arch design.

Firstly, all these privacy feature are hardware level privacy solution.  
Dell is going to implement  some other dell privacy devices using interface acpi and  wmi differently.
such as electronic privacy display, privacy camera, and other privacy technology that is coming soon.
we need to have dell-privacy-acpi and dell-privacy-wmi files to handle the privacy device interaction with BIOS and EC(embedded controller)
  - the dell-privacy-wmi file handle the wmi event from BIOS and emit it to userspace , it is wmi interface related driver file.
  - the dell-privacy-acpi interact with ACPI interface ,dell privacy feature need to send ACK content to EC  through ACPI interface.
  - other privacy device function will be developed according to the interface type. the two driver files will be extended for new devices.

Meanwhile, actually we will consider to add one ACPI device to BIOS DSDT table in future , then dell-privacy-acpi driver can register to kernel matching that device with specific ACPI device ID.

If you have any other concerns for arch design , Mario could help to explain some more details to get this clear.