On 06/15/2012 08:44 PM, Jeff Weber wrote:
Is the FAQ line:
"The I-pipe patch currently does not support MSI interrupts."
still true? This FAQ is dated to 2008.
In retrospect, this FAQ entry is somewhat misleading. As Jan pointed out
a couple of times already, the I-pipe does handle MSI interrupts
properly, but doesn't allow non-root domains to call the IRQ
masking/unmasking code for MSI. Since unmasking is usually paired with
requesting an IRQ, and masking is paired with releasing it, the
restriction should include the request/free calls as well.
There is no reason to mask MSI in the pre-handling code due to their
semantics, and therefore no reason to unmask them upon return from the
handler, so the restriction turns out to be a non-issue for most use
cases. If a primary domain handler really wants to prevent more MSI to
come from a given source, then it should quiesce the issuing device.
I've been using MSIs and adeos-ipipe-2.6.38.8-x86-2.10-01.patch and haven't
seen a problem yet.
--
Philippe.
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