Date: Tue, 18 Jan 2000 13:22:21 -0800 From: Mike Smith <msmith@freebsd.org> To: Warner Losh <imp@village.org> Cc: Mike Smith <msmith@FreeBSD.ORG>, Tatsumi Hosokawa <hosokawa@itc.keio.ac.jp>, mobile@FreeBSD.ORG Subject: Re: Working pcic polling mode patch (Re: Polling mode of pcic as default?) Message-ID: <200001182122.NAA01429@mass.cdrom.com> In-Reply-To: Your message of "Mon, 17 Jan 2000 22:42:27 MST." <200001180542.WAA14505@harmony.village.org>
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> In message <200001170922.BAA02947@mass.cdrom.com> Mike Smith writes: > : Definitely not. The IRQ should be determined by examining the machine's > : actual resource configuration, with a manual override from the loader. > : Of all the possible sources of IRQ configuration information, the kernel > : configuration file is the most likely to be wrong. > > Why is pcic different than every other device in the entire system? > If I want to change the IRQ for a sio line, I do it in userconfig, not > some whacked out kernel loader env variable. Why should PCIC be > different? Er, because it _is_ different. With sio devices, you have a set of hardcoded configurations that are 'typical', and PnP information (which we mishandle in the case when it matches the hardcoded expectations). The pcic is a totally different animal in some respects; in particular, its IRQ needs to be selected based on what's actually available in the system; something that cannot possibly be determined correctly in a pre-built kernel. Using an environment variable is just a placeholder for userconfig becoming a real hint editor; making the pcic IRQ settable inside userconfig would require a heap more work than anyone wants to spend. > Also, this rusian roulette of picking an IRQ is unwise. It breaks too > many times. You must hardwire the IRQ, or use polling. Examining the > machine is too unreliable to work. Er, hardwiring is just persistent state based on examining the machine. This is an argument for a polling-only approach. -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-mobile" in the body of the message
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