Mon, Oct 11, 2021 at 04:02:43PM +0100, Richard F wrote:
Powersaving for DVB receivers - try the attached patch from glenvt18
Thank you. I will test it later once I have hooked up the Raspberry Pi to my laboratory power supply so that I can observe the total power consumption.
While "uhubctl -a off" would cause an optimal mouse to power off its LED, it will not completely cut the power. I tested this by plugging in a mobile phone to the USB port. It indicated that charging is available.
One impact of "uhubctl -a off" is that any plug/unplug events for the affected ports will be disabled, and "lsusb" will reflect the state as it was before the invocation.
I just confirmed with a laboratory power supply that my USB DVB-T/T2/C stick is consuming 61 mA at 5 volts. If I remember correctly, USB devices are allowed to drain up to 100 mA without any negotiation, so it should not be out-of-spec. Those additional 0.35 watts should be a significant portion of the total power consumption. I did not measure yet, but I hope it to be in the range of 2 to 3 watts.
For my use case, I think that I will only configure udev events for inserting or removing the stick. No shutdown command would be configured in VDR. I would abruptly shut down VDR and lircd by unplugging the adapter. They would observe the abrupt loss of DVB hardware, followed by a terminating signal sent by systemd or udevd.
Best regards, Marko _______________________________________________ vdr mailing list vdr@xxxxxxxxxxx https://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr
