Hi, On 26-Nov-24 6:12 PM, Ricardo Ribalda wrote: > On Tue, 26 Nov 2024 at 17:51, Laurent Pinchart > <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: >> >> On Tue, Nov 26, 2024 at 05:27:57PM +0100, Ricardo Ribalda wrote: >>> On Mon, 25 Nov 2024 at 22:35, Laurent Pinchart wrote: >>>> On Mon, Nov 25, 2024 at 03:41:19PM +0100, Hans de Goede wrote: >>>>> On 25-Nov-24 2:14 PM, Laurent Pinchart wrote: >>>>>> On Mon, Nov 25, 2024 at 01:01:14PM +0100, Hans de Goede wrote: >>>>>>> On 18-Nov-24 5:47 PM, Ricardo Ribalda wrote: >>>>>>>> On Mon, 18 Nov 2024 at 16:43, Hans de Goede wrote: >>>>>>>>> On 15-Nov-24 9:20 AM, Ricardo Ribalda wrote: >>>>>>>>>> On Fri, 15 Nov 2024 at 00:06, Laurent Pinchart wrote: >>>>> >>>>> <snip> >>>>> >>>>>>>>>>> Is there any ACPI- or WMI-provided information that could assist with >>>>>>>>>>> associating a privacy GPIO with a camera ? >>>>>>> >>>>>>> I just realized I did not answer this question from Laurent >>>>>>> in my previous reply. >>>>>>> >>>>>>> No unfortunately there is no ACPI- or WMI-provided information that >>>>>>> could assist with associating ACPI/WMI camera privacy controls with >>>>>>> a specific camera. Note that these are typically not exposed as a GPIO, >>>>>>> but rather as some vendor firmware interface. >>>>>>> >>>>>>> Thinking more about this I'm starting to believe more and more >>>>>>> that the privacy-control stuff should be handled by libcamera >>>>>>> and then specifically by the pipeline-handler, with some helper >>>>>>> code to share functionality where possible. >>>>>>> >>>>>>> E.g. on IPU6 equipped Windows laptops there may be some ACPI/WMI >>>>>>> driver which provides a /dev/input/event# SW_CAMERA_LENS_COVER node. >>>>>> >>>>>> Using an event device means that the user would need permissions to >>>>>> access it. Would distributions be able to tell the device apart from >>>>>> other event devices such as mouse/keyboard, where a logged user may not >>>>>> have permission to access all event devices in a multi-seat system ? >>>>> >>>>> input events modaliases contain a lot of info, including what sort >>>>> of events they report, e.g. : >>>>> >>>>> [hans@shalem uvc]$ cat /sys/class/input/input36/modalias >>>>> input:b0003v046Dp405Ee0111-e0,1,2,3,4,11,14,k71,72,73,74,75,77,78,79,7A,7B,7C,7D,7E,7F,80,81,82,83,84,85,86,87,88,89,8A,8B,8C,8E,8F,90,96,98,9B,9C,9E,9F,A1,A3,A4,A5,A6,A7,A8,A9,AB,AC,AD,AE,B0,B1,B2,B3,B4,B5,B6,B7,B8,B9,BA,BB,BC,BD,BE,BF,C0,C1,C2,CC,CE,CF,D0,D1,D2,D4,D8,D9,DB,DF,E0,E1,E4,E5,E6,E7,E8,E9,EA,EB,F0,F1,F4,100,110,111,112,113,114,115,116,117,118,119,11A,11B,11C,11D,11E,11F,161,162,166,16A,16E,172,174,176,177,178,179,17A,17B,17C,17D,17F,180,182,183,185,188,189,18C,18D,18E,18F,190,191,192,193,195,197,198,199,19A,19C,1A0,1A1,1A2,1A3,1A4,1A5,1A6,1A7,1A8,1A9,1AA,1AB,1AC,1AD,1AE,1AF,1B0,1B1,1B7,1BA,240,241,242,243,244,245,246,247,248,249,24A,24B,24C,24D,250,251,260,261,262,263,264,265,r0,1,6,8,B,C,a20,m4,l0,1,2,3,4,sfw >>>>> >>>>> So I believe that we can create a udev rule which matches on input >>>>> devices with SW_CAMERA_LENS_COVER functionality and set a uaccess >>>>> tag on those just like it is done for /dev/video# nodes. >>>>> >>>>> Or we can just use a specific input-device-name (sub) string >>>>> and match on that. >>>>> >>>>> This may require using a separate input_device with just >>>>> the SW_CAMERA_LENS_COVER functionality in some of the laptop >>>>> ACPI / WMI drivers, but that is an acceptable compromise IMHO. >>>> >>>> As long as it's doable I'm OK with it. >>>> >>>>> (we don't want to report privacy sensitive input events on >>>>> these nodes to avoid keylogging). >>>>> >>>>>> Would compositors be able to ignore the device to let libcamera handle >>>>>> it ? >>>>> >>>>> input devices can be opened multiple times and we want the compositor >>>>> to also open it to show camera on/off OSD icons / messages. >>>> >>>> I'm not sure we want that though, as the event should be associated with >>>> a particular camera in messages. It would be better if it still went >>>> through libcamera and pipewire. >>> >>> For OSD we do not necessarily need to know what camera the GPIO is >>> associated with. >>> >>> We just want to give instant feedback about a button on their device. >>> Eg in ChromeOS we just say: "camera off" not "user facing camera off" >> >> That may be true of Chrome OS, but in general, other systems may want to >> provide more detailed information. I wouldn't model the API and >> architecture just on Chrome OS. > > It is not about ChromeOS, it is about the use case. > > We were talking about 2 usecases: > - instant feedback for a button. Actor: OSD / composer > - this camera is disabled, please use other camera or enable it: Actor > camera app, or camera "service" (read pipewire, libcamera, or the > permission handler for snap) > > There are some examples showing that for "instant feedback" there is > no need to link the event to the camera: > - there is hardware where this is not possible to establish the link. > - ChromeOS does not show the camera name (when it has enough > information to do so) > - I believe Hans mentioned that Windows does not show the camera name. > - (Hans, are you wiring SW_CAMERA_LENS_COVER to the user right now?) > Do you know of a system where this info is needed? I would like to see this wired up in GNOME but I'm not aware of anyone actively working on this. I expect that for GNOME a simple OSD with a camera icon with / without a cross through it will suffice and I expect such a simple implementation to directly talk to libinput at the compositor level. If GNOME does ever wants to show a label on the OSD with a description of which camera it applies to, like it currently does for volume up/down/ mute keys which affect the current default sound output), then I would expect it to talk to pipewire to get the events instead of directly through libinput. Either scenario can be supported with the SW_CAMERA_LENS_COVER userspace API, so IMHO this is an implementation detail which can be left up to whomever implements this for GNOME. FWIW if I were to implement this myself I would go for the simple solution of not showing a camera description like ChromeOS is currently doing. Regards, Hans
