Hi Wentong, On Fri, Feb 17, 2023 at 06:28:32AM +0000, Wu, Wentong wrote: > > > > -----Original Message----- > > From: Bingbu Cao <bingbu.cao@xxxxxxxxxxxxxxx> > > Sent: Friday, February 17, 2023 9:44 AM > > > > Hi, Sakari, > > > > On 2/16/23 9:12 PM, Sakari Ailus wrote: > > > Hi Bingbu, Wentong, > > > > > > On Wed, Feb 15, 2023 at 08:09:50PM +0800, Bingbu Cao wrote: > > >> > > >> Hi, Wentong, > > >> > > >> On 2/15/23 5:43 PM, Laurent Pinchart wrote: > > >>> Hello Wentong, > > >>> > > >>> On Mon, Feb 13, 2023 at 10:23:44AM +0800, Wentong Wu wrote: > > >>>> Intel Visual Sensing Controller (IVSC), codenamed "Clover Falls", > > >>>> is a companion chip designed to provide secure and low power vision > > >>>> capability to IA platforms. IVSC is available in existing > > >>>> commercial platforms from multiple OEMs. > > >>>> > > >>>> The primary use case of IVSC is to bring in context awareness. IVSC > > >>>> interfaces directly with the platform main camera sensor via a > > >>>> CSI-2 link and processes the image data with the embedded AI > > >>>> engine. The detected events are sent over I2C to ISH (Intel Sensor > > >>>> Hub) for additional data fusion from multiple sensors. The fusion > > >>>> results are used to implement advanced use cases like: > > >>>> - Face detection to unlock screen > > >>>> - Detect user presence to manage backlight setting or waking up > > >>>> system > > >>> > > >>> Do you have plan to support these features in the ivsc driver in the > > >>> future ? > > >>> > > >>>> Since the Image Processing Unit(IPU) used on the host processor > > >>>> needs to configure the CSI-2 link in normal camera usages, the > > >>>> CSI-2 link and camera sensor can only be used in mutually-exclusive > > >>>> ways by host IPU and IVSC. By default the IVSC owns the CSI-2 link > > >>>> and camera sensor. The IPU driver can take ownership of the CSI-2 > > >>>> link and camera sensor using interfaces provided by this IVSC driver. > > >>>> > > >>>> Switching ownership requires an interface with two different > > >>>> hardware modules inside IVSC. The software interface to these > > >>>> modules is via Intel MEI (The Intel Management Engine) commands. > > >>>> These two hardware modules have two different MEI UUIDs to enumerate. > > These hardware modules are: > > >>>> - ACE (Algorithm Context Engine): This module is for algorithm > > >>>> computing when IVSC owns camera sensor. Also ACE module controls > > >>>> camera sensor's ownership. This hardware module is used to set ownership > > of camera sensor. > > >>>> - CSI (Camera Serial Interface): This module is used to route > > >>>> camera sensor data either to IVSC or to host for IPU driver and application. > > >>>> > > >>>> IVSC also provides a privacy mode. When privacy mode is turned on, > > >>>> camera sensor can't be used. This means that both ACE and host IPU > > >>>> can't get image data. And when this mode is turned on, host IPU > > >>>> driver is informed via a registered callback, so that user can be notified. > > >>> > > >>> How does the privacy mode work, and how can the user trust that the > > >>> closed-source IVSC and IME firmwares will honour the privacy settings ? > > > > As I know, without IVSC, once user enable the privacy mode, the Intel > > Converged Security Engine will configure the IPU camera mask (security register), > > which will mask the specific CSI2 port and produce dummy imaging data. For the > > case with IVSC, there is no final solution on Linux so far I think. > > > > Wentong, is IVSC trying to cut off the stream and then notify user and IPU? > > yes Does the CSI-2 transmitter on IVCS go to some LP mode during this time, or does the receiver need to initialise the bus again when the stream resuems? > > > > > >>> > > >> > > >> Continue with question from Laurent, > > >> > > >> How IVSC handle the privacy request from user? Is there some > > >> notification mechanism to user-space? > > IVSC has already defined privacy callback for host IPU/camera driver. > > > > I'd have concern if IVSC driver > > >> need private callback to request back-end(e.g. ISP driver) to handle stream > > cutting. > > > > > > How does the privacy mode work, does it just pass zeroes (or other > > > dummy > > > data) towards the host or nothing? > > No data on CSI transmitter side Can it stop in the middle of the frame? Or is it guaranteed to produce full frames (assuming the sensor does)? > > > > > > > A V4L2 control can be used for the purpose of passing the information > > > to the user space at least. > > I will take some time to review V4L2 sub-device and control mechanism, > and then update the driver. -- Kind regards, Sakari Ailus
