<<On Thu, 9 Nov 2000 19:31:26 +1100 (EST), Bruce Evans <[EMAIL PROTECTED]> 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
[EMAIL PROTECTED] | 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
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