Re: [PATCH] Re: 2.6.17-rc5-git1: regression: resume from suspend(RAM) fails: libata issue

[Jeff Garzik <jeff@garzik.org>]

Linus Torvalds wrote:
> 
> On Sat, 27 May 2006, Jeff Garzik wrote:
>> It is.  But I thought you wanted something that works?  :)
> 
> I want something that can be _understood_ to work, and that clearly 
> doesn't have any downsides.
> 
> Waiting for the target to not be BUSY at resume is such an obviously 
> understandable thing that it's not even funny.

s/target/bus/, agreed.

Remember there might be two devices attached (master/slave), so for the 
master/slave case we will wait for BSY twice, both times with the master 
selected.


> In contrast, having an unconditional half-second delay for each SATA port 
> is not obvious at all, and has potentially huge downsides for totally 
> unrelated users. 

Incorrect:  half-second for each _controller_.

And the only users affected by the delay are ata_piix users doing resume.

Side note -- do you notice that the suspend is really hardcoded for 
ata_piix and Intel laptops at the moment?  Note ata_set_mode() versus 
->set_mode(), complete lack of controller re-init, etc.


>> Your patch + Jens' patch [with the delay MOVED to the end] would get my ACK
>> for 2.6.17, and we already have infrastructure queued for 2.6.18 to do a
>> better job of kicking the controller and bus.
> 
> No way am I adding a random half-second wait. One _millisecond_ or 
> something similar clearly won't impact anybody else. But half a second for 
> a condition that people don't even understand?

Normally I would agree, but the delay would be immediately removed for 
2.6.18.  libata-dev.git#upstream has reorganized the probe code to 
better support this case as well as hotplug.  And in general #upstream 
recovers from errors A LOT better.

So AFAICS there are three paths to success:

1) Apply Jens' patch for 2.6.17, then undo it in 2.6.18 when #upstream 
is merged.

2) Copy a bunch of code into pci_driver::resume and more into 
ata_device_resume(), to do controller and phy init.  And then remove the 
copied code in 2.6.18 when #upstream is merged.

3) Pull #upstream now, and give us another -rc to fix things.

	Jeff