Date: Thu, 9 Nov 2000 11:01:06 -0500 (EST) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: Bruce Evans <bde@zeta.org.au> Cc: current@FreeBSD.ORG Subject: Interrupt allocation Message-ID: <200011091601.LAA06059@khavrinen.lcs.mit.edu> In-Reply-To: <Pine.BSF.4.21.0011091859420.7845-100000@besplex.bde.org> References: <200011082018.NAA32387@harmony.village.org> <Pine.BSF.4.21.0011091859420.7845-100000@besplex.bde.org>
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<<On Thu, 9 Nov 2000 19:31:26 +1100 (EST), Bruce Evans <bde@zeta.org.au> said: > - pci drivers "know" that pci interrupts are shareable and force > RF_SHAREABLE. Is this required by the pci spec? Yes. > - the isa compatibility code and pcvt force RF_SHAREABLE although isa > irqs are rarely shareable. This is a bug. I suspect it may be due to code rot, related to the removal of the ``conflicts'' keyword in config. > - sio forces !RF_SHAREABLE, but it is possible for sio interrupts to be > shared if they aren't fast. Well, you're welcome to make it do whatever you think is correct. > This overloads RF_SHAREABLE to mean that the device driver > supports sharing. Whether sharing is supported should not be an attribute of the device driver -- all drivers should support interrupt sharing, even in cases where the underlying hardware is ``known'' not to support it. (Having the drivers specify RF_SHAREABLE is a bug I introduced when I did the first port to new-bus.) If there are buses which need to be programmed to enable or disable sharing, that should be handled through a bus-specific mechanism (preferably automatically). Timesharing requires co-operation from both device and bus, but this is a completely different issue. No drivers currently support timesharing. `sio' at a minimum probably should, as it was the motivating example for adding that feature. (My laptop has three PnP sio ports: an internal modem, an external DB-9, and a dual-ported infrared transceiver. There are only two interrupts available among them.) -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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