Date: Thu, 22 May 1997 16:07:52 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: brett@lariat.org (Brett Glass) Cc: msmith@atrad.adelaide.edu.au, gurney_j@resnet.uoregon.edu, rberndt@nething.com, WELCHDW@wofford.edu, HARDWARE@FreeBSD.ORG Subject: Re: isa bus and boca multiport boards Message-ID: <199705220637.QAA19080@genesis.atrad.adelaide.edu.au> In-Reply-To: <3.0.1.32.19970521231927.006a1a5c@lariat.org> from Brett Glass at "May 21, 97 11:19:27 pm"
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Brett Glass stands accused of saying: > At 01:51 PM 5/22/97 +0930, Michael Smith wrote: > > >The state of the 'gone' flag may (possibly) change > >_during_the_execution_ of the ISR. > > If so, it sounds as if there might be major synchronization and reentrancy > problems. Not to mention logic glitches if the port goes away at the wrong > moment. Heh. Welcome to PCMCIA. TBH, I suspect that it's unlikely that the card is going to be flagged as gone during the interrupt handler, but it's impossible to tell that it's gone until after it already has. > >the 8250 family UARTS, and macrocells compatible with them, are used > >on a staggering array of computing hardware. Look at the Alpha > >platforms that are a hot FreeBSD port target for example. > > In which case, they can stick with the C version -- or, if they need > performance, do a tuned ASM version for that processor. ... or use a C version that just happens to be highly optimised. It just occurred to me that the author of the BNU FOSSIL driver is probably reading this. David, would you care to comment on the 'sio' driver, or do you know Bruce too well? -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[
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