Joerg Reisenweber wrote: > Am Mo 20. Oktober 2008 schrieb Alastair Johnson: >> Werner Almesberger wrote: >>> I order to evaluate the impact of the AT%SLEEP=2 work-around, Joerg >>> asked me to measure how the sleep mode affects the current drawn by >>> the system. >>> >>> Test setup: >>> >>> - device is idle but (for convenience) not suspended >>> - GSM is active and has registered with the network (AT+CFUN=1, >>> AT+COPS=0) >>> - the test setup does not suffer from #1024 >>> - power is supplied to the battery terminals from a lab power supply >>> set to 4.0V >>> - USB is not connected >>> >>> Battery current of the whole system in mA. Values are from measurements >>> averaged over about 15 minutes each: >>> >>> at%sleep= avg min max samples >>> 4 96.0 91.6 198.0 20006 >>> 3 98.4 91.6 214.6 21432 >>> 2 102.2 97.6 209.3 21428 >>> 1 104.0 101.9 197.2 21352 >>> 0 120.3 118.8 213.0 21452 >>> >>> Integration period is one power line cycle (20ms). There are transients >>> much faster than 50Hz. E.g., sampling at 2.5kHz finds more noise but >>> does not change the difference in the averaged value: >>> >>> at%sleep= avg min max samples >>> 4 95.1 63.1 242.5 210207 >>> 3 97.1 62.8 242.9 215460 >>> 2 101.4 68.7 243.4 208230 >>> >>> Note that this is an idle but not suspended system, hence the large >>> minimum current. >>> >>> So the difference between sleep=2 and sleep=4 is about 6mA. Joerg >>> mentioned that the idle current of the GSM subsystem should be 4mA, >>> so this would be an increase to 250%. >>> >>> Andy, you once measured the power consumption when the overall system >>> is perfectly suspended. Do you still remember how much it was ? >>> >>> - Werner >> Can you repeat the test on a handset that is suffering from #1024? I >> suspect that the frequent reregisters increase power consumption, but I >> don't have the equipment available to make the measurements. It >> certainly produces more instances of GSM interference on my PC speakers >> which suggests more transmit operations. If this is the case then for >> those wth #1024 SLEEP=2 may be no worse, or possibly better, than SLEEP=4. > > that's the idea behind Mickey's recent bandaid, switching to SLEEP=2 on > detecting #1024 behaviour > /j
I thought the idea was to make GSM usable for people suffering from #1024 :-) Mickey suggests the bandaid may make power consumption worse in comment 45. I may have missed something, but I haven't seen any hard evidence on the effect of #1024 on power consumption. Werner's results show the difference between SLEEP=4 and SLEEP=2 for a phone without #1024. I would like to see the same test done with #1024 to provide evidence on the effect of reregistration on power consumption. I have intermittent problems with #1024, and the patches won't make any difference if the phone is suspended when the problem starts. I also see big variations in battery life while suspended. If #1024 has no significant effect on power consumption then I can rule it out as a possible cause and look elsewhere. _______________________________________________ hardware mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/hardware
