From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ronald G Minnich To: <9fans@cse.psu.edu> Subject: Re: [9fans] IRQs again... In-Reply-To: <6c155793a8bde8d42d7c371d52d4476a@plan9.bell-labs.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Date: Mon, 27 May 2002 12:55:00 -0600 Topicbox-Message-UUID: 9d91f184-eaca-11e9-9e20-41e7f4b1d025 On Mon, 27 May 2002, David Gordon Hogan wrote: > I would like to suggest that since LinuxBios has "BIOS" in > the name, that it should allocate IRQs to the various devices > as part of system initialisation, as this appears to be one of > the (de facto) jobs of the BIOS. Every other BIOS does it. No. Sorry. There are good reasons for this and it ain't going to happen. We've been over this ground quite a bit over the last 2 years. The OS has a way better idea of what it needs, and once you start pulling in nonsense like SMP and APIC and IO-APIC it gets very very messy. The odds that the BIOS can get things set up right for the OS become vanishingly small. I'm still a little lost on how you plan to handle the hot plug thing. What do you plan to do if the device is not there until after the OS boots? Or goes away? do you reclaim the interrupt or not? Do you plan to callback to the BIOS? We don't do callbacks either. Of course Andrey might force me to change my mind. > We've thought about what it would take to make Plan 9 > do this instead, and generally reached the conclusion > that it would be a Bad Thing. can you elaborate? I just don't agree, and neither (it seems) do the other open source OSes out there. But I've been wrong lots of times so if you have a solid reason I'm all ears. ron