Arch Linux

nTia89

Banned

From: varese, italy

Registered: 2008-12-22

Posts: 1,230

[SOLVED] webcam drain power

Hi fellows,
today I run `lsusb.py` command.
Below the output:

[mattia@arch-xps ~]$ lsusb.py 
usb1             1d6b:0002 09  2.00  480MBit/s 0mA 1IF  (Linux 4.5.1-1-ARCH xhci-hcd xHCI Host Controller 0000:00:14.0) hub
 1-2             2109:2812 09  2.10  480MBit/s 0mA 1IF  (VIA Labs, Inc.          USB2.0 Hub             ) hub
  1-2.1          0fe6:9700 00  1.10   12MBit/s 120mA 1IF  (Kontron (Industrial Computer Source / ICS Advent) DM9601 Fast Ethernet Adapter)
  1-2.4          1e7d:2d50 00  1.10   12MBit/s 100mA 2IFs (ROCCAT ROCCAT Kova[+])
 1-3             0a5c:216f ff  2.00   12MBit/s 0mA 4IFs (Broadcom Corp BCM20702A0 346895ED9C26)
 1-5             0bda:5682 ef  2.01  480MBit/s 500mA 2IFs (CKFEH41L054020008290 Integrated_Webcam_HD 200901010001)
usb2             1d6b:0003 09  3.00 5000MBit/s 0mA 1IF  (Linux 4.5.1-1-ARCH xhci-hcd xHCI Host Controller 0000:00:14.0) hub
 2-2             2109:0812 09  3.00 5000MBit/s 0mA 1IF  (VIA Labs, Inc.          USB3.0 Hub             ) hub

Casually and sadly I noted the power (current) consumption of the sixth device, that is the laptop's webcam.

Webcam were powered off, or better, was not in use when I run that command.
And oddly, if I launch Cheese in order to use the webcam, the current doesn't change.
First, this last is really strange. Does it mean webcam is always powered on?
Second, how can I power off it?

NB: I don't want to completely remove the webcam feature, that's what happen if I unload the `uvcvideo` module... instead I'd like to find a way to suspend the camera

thank you

EDIT: even if I unload `uvcvideo` module, as archwiki suggests, power consumption change, that's really weird!

Last edited by nTia89 (2016-04-28 15:35:16)

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+pc: custom | AMD Opteron 175 | nForce4 Ultra | 2GB ram DDR400 | nVidia 9800GT 1GB | ArchLinux x86_64 w/ openbox
+laptop: Apple | MacBook (2,1) | 2GB ram | Mac OS X 10.4 -> DIED
+ultrabook: Dell | XPS 13 (9343) | 8GB ram | 256GB ssd | FullHD display | Windows 8.1 64bit ArchLinux x86_64 w/ Gnome

ooo

Member

Registered: 2013-04-10

Posts: 1,638

Re: [SOLVED] webcam drain power

Did you try enabling USB autosuspend?
https://wiki.archlinux.org/index.php/Po … utosuspend

nTia89

Banned

From: varese, italy

Registered: 2008-12-22

Posts: 1,230

Re: [SOLVED] webcam drain power

according to `tlp` that feature seems already enabled, for all devices:

+++ USB
autosuspend        = enabled
device whitelist   = (not configured)
device blacklist   = (not configured)
wwan blacklist     = enabled

Bus 002 Device 002 ID 2109:0812 control = auto, autosuspend_delay_ms =     0 -- VIA Labs, Inc. VL812 Hub (hub)
Bus 002 Device 001 ID 1d6b:0003 control = auto, autosuspend_delay_ms =     0 -- Linux Foundation 3.0 root hub (hub)
Bus 001 Device 003 ID 0bda:5682 control = auto, autosuspend_delay_ms =  2000 -- Realtek Semiconductor Corp.  (uvcvideo)
Bus 001 Device 002 ID 0a5c:216f control = on,   autosuspend_delay_ms =  2000 -- Broadcom Corp. BCM20702A0 Bluetooth (btusb)
Bus 001 Device 006 ID 1e7d:2d50 control = on,   autosuspend_delay_ms =  2000 -- ROCCAT Kova+ Mouse (usbhid)
Bus 001 Device 005 ID 0fe6:9700 control = on,   autosuspend_delay_ms =  2000 -- Kontron (Industrial Computer Source / ICS Advent) DM9601 Fast Ethernet Adapter (dm9601)
Bus 001 Device 004 ID 2109:2812 control = auto, autosuspend_delay_ms =     0 -- VIA Labs, Inc. VL812 Hub (hub)
Bus 001 Device 001 ID 1d6b:0002 control = auto, autosuspend_delay_ms =     0 -- Linux Foundation 2.0 root hub (hub)

---

+pc: custom | AMD Opteron 175 | nForce4 Ultra | 2GB ram DDR400 | nVidia 9800GT 1GB | ArchLinux x86_64 w/ openbox
+laptop: Apple | MacBook (2,1) | 2GB ram | Mac OS X 10.4 -> DIED
+ultrabook: Dell | XPS 13 (9343) | 8GB ram | 256GB ssd | FullHD display | Windows 8.1 64bit ArchLinux x86_64 w/ Gnome

The Loko

Member

From: Spain

Registered: 2014-07-23

Posts: 100

Re: [SOLVED] webcam drain power

I think that is the rated webcam current not the actual current, it means that the webcam requests the USB port to supply that current but it may not use it all the time.

Last edited by The Loko (2016-04-28 11:07:46)

nTia89

Banned

From: varese, italy

Registered: 2008-12-22

Posts: 1,230

Re: [SOLVED] webcam drain power

mhhh, maybe .... you're right
because `lsusb -v` shows the entry:

MaxPower      500mA

[SOLVED]

why does the forth entry (Broadcom Corp. BCM20702A0 Bluetooth (btusb)) have 0 mA ?

EDIT: typo

Last edited by nTia89 (2016-04-28 15:35:01)

---

+pc: custom | AMD Opteron 175 | nForce4 Ultra | 2GB ram DDR400 | nVidia 9800GT 1GB | ArchLinux x86_64 w/ openbox
+laptop: Apple | MacBook (2,1) | 2GB ram | Mac OS X 10.4 -> DIED
+ultrabook: Dell | XPS 13 (9343) | 8GB ram | 256GB ssd | FullHD display | Windows 8.1 64bit ArchLinux x86_64 w/ Gnome