Date: Sun, 12 Aug 2001 10:02:37 -0600 From: Warner Losh <imp@harmony.village.org> To: Joe Kelsey <joe@zircon.seattle.wa.us> Cc: freebsd-current@FreeBSD.ORG Subject: Re: Mouse flags? Message-ID: <200108121602.f7CG2bW01274@harmony.village.org> In-Reply-To: Your message of "Sat, 11 Aug 2001 22:35:30 PDT." <15222.5538.796294.673437@zircon.zircon.seattle.wa.us> References: <15222.5538.796294.673437@zircon.zircon.seattle.wa.us>
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In message <15222.5538.796294.673437@zircon.zircon.seattle.wa.us> Joe Kelsey writes: : Where is the evidence that any errors have ever occurred on the ps2 : port? What sort of errors should one expect to occur? Surely not : parity errors. The only possible errors are if you use a mechanical : switch (such as Mike Smith) and you flip the switch in the middle of a : mouse operation. . Therefore, I would expect Mike Smith to experience a : multitude of errors, whereas those of us using electronic KVM switches : should never experinece a single error. When the mouse is switched in and out, I've seen extra or missing bytes in the data stream. I've seen this even on a mouse that wasn't moving at all. I've long suspected, but haven't dived deep enough in the code to verify, that mice initialize to one packet format, and the driver puts it into a different format as part of its initialization. That disconnect is why the mouse never works if you do the mechanical switch route, since it disconnects power as part of the switch process. So just ripping out the error detection/correction code won't help much at all. Like I said above, this is specualtion. I found the psm driver a little hard to penetrate, so I never followed up on this at all. It was the only theory I ever came up with that explained things. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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