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From: Baoquan He <bhe@redhat.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: linux-kernel@vger.kernel.org
Subject: A question about state machine function state_next()
Date: Mon, 1 Jun 2015 11:09:40 +0800	[thread overview]
Message-ID: <20150601030940.GK6353@dhcp-128-28.nay.redhat.com> (raw)

Hi Joerg,

I am reading amd iommu code because I have some knowledge about intel
iommu since review Zhenhua's fixing kdump error patches. Now there's
a question I didn't find answer.

In amd iommu state_next() is the state machine running function. However
I only found 4 function to call iommu_go_to_state() to change the state,
they are:
amd_iommu_detect()
amd_iommu_prepare()
amd_iommu_enable()
amd_iommu_init()

And they are called according to above sequence. It means only below 4
cases are checked and the code blocks are executed. Then where to call
amd_iommu_enable_interrupts() and amd_iommu_init_dma(). Could you help
to tell what I missed?

static int __init state_next(void)
{
	int ret = 0;

	switch (init_state) {
	case IOMMU_START_STATE:     //checked and execute
	case IOMMU_IVRS_DETECTED:   //checked and execute
	case IOMMU_ACPI_FINISHED:   //checked and execute
	case IOMMU_ENABLED:         //checked and execute
	...
}

Thanks
Baoquan

             reply	other threads:[~2015-06-01  3:09 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-01  3:09 Baoquan He [this message]
2015-06-01  6:42 ` A question about state machine function state_next() Joerg Roedel
2015-06-01  9:09   ` Baoquan He
2015-06-01  9:21     ` Joerg Roedel
2015-06-01 10:19       ` Baoquan He
2015-06-01 10:33         ` Joerg Roedel
2015-06-01 11:11           ` Baoquan He
2015-06-01 11:18       ` Baoquan He
2015-06-01 12:01         ` Joerg Roedel
2015-06-01 14:01           ` Baoquan He

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