From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: "Li, Shaohua" <shaohua.li@intel.com>
Subject: Re: 2.6.12-rc1-mm3: box hangs solid on resume from disk while resuming device drivers
Date: Sat, 26 Mar 2005 19:23:51 +0100
User-Agent: KMail/1.7.1
Cc: "Andrew Morton" <akpm@osdl.org>, "Brown, Len" <len.brown@intel.com>,
       linux-kernel@vger.kernel.org, "Pavel Machek" <pavel@suse.cz>
References: <16A54BF5D6E14E4D916CE26C9AD30575017EDC38@pdsmsx402.ccr.corp.intel.com> <200503251519.22680.rjw@sisk.pl>
In-Reply-To: <200503251519.22680.rjw@sisk.pl>
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Hi,

On Friday, 25 of March 2005 15:19, Rafael J. Wysocki wrote: 
> On Friday, 25 of March 2005 13:54, you wrote:
> ]--snip--[
> > >My box is still hanged solid on resume (swsusp) by the drivers:
> > >
> > >ohci_hcd
> > >ehci_hcd
> > >yenta_socket
> > >
> > >possibly others, too.  To avoid this, I had to revert the following
> > patch from the Len's tree:
> > >
> > >diff -Naru a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
> > >--- a/drivers/acpi/pci_link.c	2005-03-24 04:57:27 -08:00
> > >+++ b/drivers/acpi/pci_link.c	2005-03-24 04:57:27 -08:00
> > >@@ -72,10 +72,12 @@
> > > 	u8			active;			/* Current IRQ
> > */
> > > 	u8			edge_level;		/* All IRQs */
> > > 	u8			active_high_low;	/* All IRQs */
> > >-	u8			initialized;
> > > 	u8			resource_type;
> > > 	u8			possible_count;
> > > 	u8			possible[ACPI_PCI_LINK_MAX_POSSIBLE];
> > >+	u8			initialized:1;
> > >+	u8			suspend_resume:1;
> > >+	u8			reserved:6;
> > > };
> > >
> > > struct acpi_pci_link {
> > >@@ -530,6 +532,10 @@
> > >
> > > 	ACPI_FUNCTION_TRACE("acpi_pci_link_allocate");
> > >
> > >+	if (link->irq.suspend_resume) {
> > >+		acpi_pci_link_set(link, link->irq.active);
> > >+		link->irq.suspend_resume = 0;
> > >+	}
> > > 	if (link->irq.initialized)
> > > 		return_VALUE(0);
> > 
> > How about just remove below line:
> > >+		acpi_pci_link_set(link, link->irq.active);
> 
> You mean apply the patch again and remove just the single
> line?  No effect (ie hangs).

It looks like removing this line couldn't help.

Apparently, acpi_pci_link_set(link, link->irq.active) must be called
_before_ the call to pci_write_config_word() in
drivers/pci/pci.c:pci_set_power_state(), because the box hangs
otherwise.  However, with the patch applied,
acpi_pci_link_set(link, link->irq.active) is only called through
pcibios_enable_irq() in pcibios_enable_device(), which is _after_
the call to pci_set_power_state() in pci_enable_device_bars(),
so it's too late.

Hence, it seems, if you really want to get rid of the
irqrouter_resume(), whatever the reason, the simplest fix
seems to be to change the order of calls to pci_set_power_state()
and pcibios_enable_device() in pci_enable_device_bars():

--- old/drivers/pci/pci.c	2005-03-26 19:10:09.000000000 +0100
+++ linux-2.6.12-rc1-mm2/drivers/pci/pci.c	2005-03-26 19:10:54.000000000 +0100
@@ -442,9 +442,9 @@ pci_enable_device_bars(struct pci_dev *d
 {
 	int err;
 
-	pci_set_power_state(dev, PCI_D0);
 	if ((err = pcibios_enable_device(dev, bars)) < 0)
 		return err;
+	pci_set_power_state(dev, PCI_D0);
 	return 0;
 }
 
though I'm not sure if that's legal.

Greets,
Rafael 


-- 
- Would you tell me, please, which way I ought to go from here?
- That depends a good deal on where you want to get to.
		-- Lewis Carroll "Alice's Adventures in Wonderland"
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