42 ms·
I wonder how it does this - does it check for the USB input, or does it check for scroll lock to be turned on (ie. LED 0x03)? If it were the latter, I could see
by judge2020 5y ago
I wonder how it does this - does it check for the USB input, or does it check for scroll lock to be turned on (ie. LED 0x03)? If it were the latter, I could see a program turning on scroll lock for the user so it could be sure new threads are immediately put on p-cores and ensuring AVX512 is available[0].
0: https://www.anandtech.com/show/17047/the-intel-12th-gen-core-i912900k-review-hybrid-performance-brings-hybrid-complexity/2 https://www.anandtech.com/show/17047/the-intel-12th-gen-core...
- bonzini 5y agoIt's almost certainly a hack based on system management mode. Not sure how it does it, but SMM is even used to emulate the PS/2 keyboard interface (at I/O ports 0x60/0x61) when all you have is a USB keyboard. So it's likely that the chipset has some kind of "backdoor" to the USB controller that can be accessed from SMM.