On Sat, Mar 3, 2012 at 12:41 AM, Peter Maydell <peter.mayd...@linaro.org> wrote: > On 2 March 2012 16:01, Anthony Liguori <anth...@codemonkey.ws> wrote: >> On 03/02/2012 06:38 AM, Zhi Yong Wu wrote: >>> Can anyone explain their relationship and difference among them? It >>> is very appreciated if you can make some comments. thanks. >> >> >> IRQ == interrupt. >> >> GPIO is just another name for an input or output pin on a chip which could >> be a IRQ line. > > The other point to note here is that there are two different sets > of terminology: > (1) real world terminology, which is roughly what Anthony is describing > (2) QEMU qdev and sysbus terms, which don't necessarily always map > quite cleanly to (1) Yeah, i also found that they don't cleanly map to real world teminology. so many interrupt concepts make me get confused.
By the way, i have one question about MSI[-X]. How does Root Complex know if one write transaction is used for MSI[-X]. When it recieves this transaction request, how it convert it to one interrupt which CPU can identify? > > In particular the QEMU type 'qemu_irq' is really just an arbitrary signal > (and would be better named GPIO) -- it is not always used for an > actual interrupt line. Can you elaborate this? > > -- PMM -- Regards, Zhi Yong Wu
