Really odd…My USB printer (HP Deskjet 970cXi) won’t stay powered off with the USB cable plugged in. If I unplug the USB cable and press the power button, the printer turns off normally. If I shut down (or sleep) linux with the USB cable plugged in, then hit the power button, the printer turns off normally. BUT if linux is running and the cable is plugged in, then I hit the power button, the following happens:
The printer cycles to off
1 second later, each panel light illuminates once
Ending with the power on light ON
This can be repeated forever with the same result - the printer is always ends up ON (not in printer sleep mode, but fully ON and ready to print).
I am running 13.1 and have the same result with each of the 4 printer drivers I have tried.
Has anyone ever seen this behavior or have any ideas about what might cause it?
According to the printer’s manual (http://h10025.www1.hp.com/ewfrf/wc/manualCategory?cc=uk&lc=en&product=61818) this model has no power management features.
I agree, but it seems to be happening anyway! Evidence that with the USB cable unplugged, pressing the “Power Off” button turns the printer off (and the “Power On” light is extinguished). With the cable plugged in, the actions described in the initial post occur. Doesn’t this insist that something within the computer (hence linux) is sending a signal to turn the printer on? Also, note that on page one of the User’s guide, it says “…Use the power button to turn the printer on and off…” - powering down is impossible with the printer’s USB cable plugged into the computer when linux is up. It just powers back up immediately without user intervention. Very strange…
On 2014-02-08 16:16, qqwasder wrote:
>
> I agree, but it seems to be happening anyway! Evidence that with the USB
> cable unplugged, pressing the “Power Off” button turns the printer off
> (and the “Power On” light is extinguished). With the cable plugged in,
> the actions described in the initial post occur. Doesn’t this insist
> that something within the computer (hence linux) is sending a signal to
> turn the printer on?
The usb cable coming from the computer has a 5 volt DC supply. This is
enough to turn many USB devices on and “think” there is a computer at
the other side, even if it is only a mains power adapter. I have some
such devices.
Other devices instead try to communicate with the host computer in order
to decide what to do. Only in this case the operating system and drivers
matter.
> Also, note that on page one of the User’s guide, it
> says “…Use the power button to turn the printer on and off…” -
> powering down is impossible with the printer’s USB cable plugged into
> the computer when linux is up. It just powers back up immediately
> without user intervention. Very strange…
You should try this same procedure with a Windows computer. If the
printer can be powered down there, then report as a bug in Bugzilla.
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” (Minas Tirith))
Maybe a passive hub between computer and printer will help here. As Carlos mentioned you may need to report as a bug.
As suggested above, could it be that the USB port in your computer is permanently powered? I read these are so to allow charging USB devices while the computer is sleeping or off. The ports are usually color-coded, the ones I’ve seen were yellow.
If that’s the case, you could try another port.
This is becoming diabolical, but there is new information. The machine has a variety of USB 2.0 and 3.0 ports - all of which yield the same results. BUT it also dual boots Windows 7 - and it (Win 7) behaves normally, i.e. I can power the printer down without it turning itself back on. The problem only exists in linux. And (I believe) only since the recent kernel upgrade to 3.11.10-7 - maybe its a minor kernel problem?
Perhaps, but as a test, you could try inserting a cheap passive hub in-line…
Unpowered hub does not effect “syndrome”. Additional info gleaned:
Turned computer off
Turned printer off
Plugged in usb cable
Powered on computer (linux boot)
Noted when printer turns on
After several rechecks, the printer appears to power up just before login is solicited (at KDM startup?).
Hmmmm…
On 2014-02-22 19:06, qqwasder wrote:
> After several rechecks, the printer appears to power up just before
> login is solicited (at KDM startup?).
Boot to text mode, runlevel 3. Wait a bit, to see if printer powers up.
Login in text mode as root, issue “init 5”.
Just to find out if it is related to KDM or earlier (cups?)
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” (Minas Tirith))