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<font size=3>At 02:05 PM 10/10/2005, Roland Dreier wrote:<br>
<blockquote type=cite class=cite cite=""> Roland>
BTW, for "INTx emulation" on PCI Express, there are no<br>
Roland> physical interrupt lines -- interrupts are
asserted and<br>
Roland> deasserted with messages. So PCI
Express interrupts are<br>
Roland> unshared.<br><br>
Michael> They are messages upstream that any
device.</font></blockquote><br>
^ sent<br><br>
Sorry. Insert "sent" above.<br><br>
<blockquote type=cite class=cite cite=""><font size=3>That doesn't parse
for me. Was what I said wrong?</blockquote><br>
No. Just clarifying that they are not unique per device. INTx
being a message does not change the fundamental semantics of a
"wire" being asserted. Hence, if the wire was shared
before, then there is no reason why this would not be the same with PCIe
sans. It really is an OS issue as to how INTx interrupts are
assigned to different processors and to what extent then end up being
shared. The host bridge can play some tricks as well as you
noted. Again, the goal within the PCI-SIG is to move people to
MSI-X and to eliminate INTx long-term. In fact, one area under
development is asking the SIG's members whether INTx can be eliminated
entirely which would go a long ways to simplifying designs both in
hardware and software.<br><br>
Mike</font></body>
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