Date: Sat, 31 Aug 1996 07:03:12 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, julian@whistle.com Cc: hackers@FreeBSD.org, pst@shockwave.com Subject: Re: gdb remote Message-ID: <199608302103.HAA21180@godzilla.zeta.org.au>
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>> The retries might be caused by UART bugs. sio context switches the >> UART registers on every `cn' i/o so that TCIOSETA on the debugger >> port can be single stepped and don't wipe out the debugger's settings. >> This works OK at typing speeds but can't work for input at high speeds >> unless the context switching is a no-op. >Can you suggest a patch to nobble this? I skip writing to the divisor registers if the divisor is already correct, but it doesn't seem to make any difference for gdb. I have no intention of single stepping through a TCIOXXXX. I have :-). Actually, the problem is more for probe/attach. You may be able to avoid opening the debugger's device, but it isn't possible to avoid probing it. >wouldn't it be better to just set a bit that stops such a TCIOSETA >from actually doing anything if it is set..? No, then debugging wouldn't be transparent. >> The -current gdb works here only after booting with -dg. I get checksum >> errors after ctl-sysreq. >same here.. works GREAT fro -gd though that's not that useful if >what you need is to repond to a breakpoint...... >breakpoints have the same effect as ctl-sysreq. Same here. ctl-sysreq essentially executes a breakpoint. Perhaps the problems is that breakpoints require lots more i/o. >presently I'm getting.... >Ignoring packet error, continuing... I get nothing except checksum errors when I hit ^C. Bruce
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