On Tue, 15 Aug 2017 18:02:57 -0400 Ken Goldman <kg...@linux.vnet.ibm.com> wrote:
> On 8/13/2017 7:53 PM, msuchanek wrote: > > About 500 out of 700 mainboards sold today has a PS/2 port which is > > probably due to prevalence of legacy devices and usbhid limitations. > > > > Similarily many boards have serial and parallel hardware ports. > > > > In all diagrams detailed enough to show these ports I have seen them > > attached to the LPC bus. > > Do these boards have a TPM? Remember that the TPM requires special > LPC bus cycles. Out of nearly 700 boards over 500 have PS/2 connector and over 400 have TPM slot (which is subset of the PS/2 enabled boards). Some more possibly have on-board TPM chip. > > Even if so, the TPM LPC bus wait states are less than a usec. My > thought is that it's unlikely that any device (serial port, mouse, > keyboard, printer) will be adversely affected. Yes, in theory this is negligible. So unless there is a possibility these wait states chain or the device otherwise takes over the bus for extended period of time this should be fine. Thanks Michal
