5 ms·
Sounds like historical revisionism. Power limiting is possible without negotiation. It's easiest, for me, to find references to the safety aspect more than anyt
by R0b0t1 6y ago
Sounds like historical revisionism. Power limiting is possible without negotiation. It's easiest, for me, to find references to the safety aspect more than anything else.
Note also a fair number of laptops (read: every one I have used and checked) use PS/2 internally because it is interrupt driven and even lower power than USB. There are also plenty of laptops that advertise high current phone charging while off, some of which do negotiation, some of which don't.
- zorgmonkey 6y agoYeah, USB is seldom inside laptops, but you might be interested to know that it is becoming increasingly common to see HID over IC2 [0] used inside of laptops instead of PS/2. [0] http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx http://msdn.microsoft.com/en-us/library/windows/hardware/hh8...
- R0b0t1 6y agoI've definitely seen it. Reusing HID is kind of clever, but the protocol is extremely bloated and hard to parse. Ignoring that, I'm not sure it's an improvement. Most of the power savings is having the keyboard initiate an interruptible event to wake the computer. Interpreting HID like in USB means the keyboard can't wake the computer, the computer needs to remain on to service USB interrupt endpoints.
- Dylan16807 6y ago> There are also plenty of laptops that advertise high current phone charging while off, some of which do negotiation, some of which don't. The laptop I had with an always-on charging port actually charged things faster in standby, because that turned off the negotiation.