[RFC, PATCH] sysdev suspend/resume order?

 
Problem:
Most of the sysdev_register calls in various devices
are being done using device_initcalls. This method of 
initialization has a side-effect, as we loose the 
ordering requirements for various resume calls. 
Order in which _resume() functions gets called during 
a resume, just depends on the order device_initcalls 
were called on these devices.

Shaohua's mail below describes one issue that is a 
result of this problem, where in pci link device get 
initialized before PIC. There can be more issues 
like this.

One solution to this problem:
Call the sysdev_registers during the actual device 
initialization. Say, i8259 sysdev_register should be 
called when i8259 device is getting registered and 
not with a device_initcall 'sometime' later.

With this, we will be able to save the original 
device initialization order (bootup order), and call 
the resume methods in the same order.

Attached are the couple of sample patches that does 
this in particular files.

Questions:
Is this solution proper?
Is there any better solution to this problem? Say 
introducing some sort of levels in device_initcall.
If the above soultion is proper, is it 
practical/feasible to audit all usages of 
sysdev_register() and try to move it to the 
device initialization function?

Thanks,
Venki

-----Original Message-----
From: Pallipadi, Venkatesh 
Sent: Friday, August 13, 2004 11:58 AM
To: Li, Shaohua; 'Patrick Mochel'
Cc: 'acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org'; Brown, Len
Subject: RE: sysdev suspend/resume order?



I think, there should be a relation between the order
in which actual device initialization happens during 
the boot time and the order in which device initcalls 
are called (at boot time).

In this example, actual PIC initialization happens 
before pci_link device initialization. So, device 
initcall should have a similar ordering. That will 
take care of this after S3 ordering in a natural manner.

Thanks,
Venki 

quoted

-----Original Message-----
From: Li, Shaohua 
Sent: Friday, August 13, 2004 12:37 AM
To: Patrick Mochel
Cc: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org; Brown, Len; Pallipadi, Venkatesh
Subject: sysdev suspend/resume order?

Patrick,
My sound card dies after S3 sometimes. Basically, if it dies 
depends on the order of sysdev's resume. If IRQ router resume 
before PIC (I use a tricky method to change order. It's 
changing the initcall level of the sysfs initialization for 
the device), the sound card die. Otherwise, it works. Is it 
possible that we add some levels for sysdev? I'd like some 
sysdevs resume before other sysdevs. Does this make sense? 

Thanks,
Shaohua