Hi, > > If the kernel has booted up, the check will not happen, so the Linux kernel > > will not get confused. > > I didn't find that the checking is necessary in protocol docs. > any hint? > > If we still use 256 size buffer in qemu, guest ps2 driver will drop > some input keys? or just delay them?
Real hardware has a 16 byte buffer. linux kernel ps/2 driver flushes everything at initialization time, probably to avoid processing stale data / incomplete ps/2 data sequences. That flush loop is limited to 16 iterations, and if the kernel maxes out the loop it is confused and fails initialization -> non-functional keyboard. cheers, Gerd
