Yeah i got that cable specifically for research purposes, at which i found out, even though it was plugged into the charger, it still wouldn't charge, as the cable only lights up when it is charging. and before i did the button fix, it would only charge while the phone was unlocked and active, but halt charging after it locked either manually or automatically. The cable lights would just stop "flowing" to the phone.
I tried connecting it to 1.1,2.1, and 3 amp connectors, even connected it to my ASUS USB port that supports the BC 1.1, but the device was NOT recognized as a compatible BC 1.1 device.
Yes i didn't know that this CPU had a built in volt regulator, but that has nothing to do with chargers, that's all internal on the CPU, also not related to the topic at hand too. I did do some research on this, and turns out that QC2.0 is really only going to utilize the 2.1A of your 3.0A charger, where as the QC3.0 being advertized by Qualcomm now is going to utilize 3.0A at a slight increase in charge capacity. Still not making it BC1.1 compatible like an iPod or iPhone, on my motherboard.
I do thank you for your feedback, but if your only experiencing slow to no charging while using the device plugged in on a 1.1A charger, that is common and misunderstood as a "problem" your device uses as much as it gets, if not more, which would result in looking like it is a glitch or error. It's ok, it seems to be more common than not, i spend most of my time redirecting customers to higher Amperages for their phones. And while yes your statement of "Amps" not mattering the device only takes what it needs, true to an extent, as where gabriel92 pointed out, you don't want to hook it up to the 5V rail on a PSU, you'll get a kaboom from your phone. Sure lower amps don't matter but you will add unneccessary strain to your battery or other internal components thus shortening the lifespan of the charge circuit or general phone components in general. Unless you have some kind of smart charger, that has an ASPM circuit built in to regulate the output automatically per the phones digital communication request, then sure, but i'm doubtful such a charger even exists. But otherwise that will all be limited by the QC2.0 of the CPU.
Electronics is something of a hobby of mine, i do appreciate the opportunity to learn about new things, but there are some things that just either make sense or don't, and that whole QC compatible charger, is not right. Gabriel92 made it clear about that, its strictly phone side, there is no intercommunication between the device and charger, it will just use what it can to charge faster, nothing really special, which still kinda holds onto the truth of what i was saying earlier. The stronger charger doesn't fix this problem though, its a battery charge controller reset needed, which is located as mentioned many times earlier. Though i have a suspicion that you aren't suffering the strange discharge or lack of charging while plugged in, i recommend grabbing a lighted cable like mine to see if it charges while the screen is locked. Cuz if not, then the only fix is that button there between the power and volume down buttons.
AND... yes i do have a fancy cable tyvm, it helped me debug this charging error.