Re: Experiences with new PCI code

> Date: Tue, 13 Apr 2004 21:23:39 -0700 (PDT)
> From: Nate Lawson <nate_at_root.org>
> 
> On Tue, 13 Apr 2004, M. Warner Losh wrote:
> > In message: <20040413220142.5F50E5D08_at_ptavv.es.net>
> >             "Kevin Oberman" <oberman_at_es.net> writes:
> > : System: IBM T30 (ICH3, 1.8G P4-M, 512 MB RAM, Intel/Xircom Pro/100 VE
> > : Ethernet, TI1520 CardBus bridge, Prism 2.5 wireless, Analog Devices
> > : AD1881A AC97 codec)
> > :
> > : After the integration of the new PCI code the suspend/resume behavior is
> > : very different than before. Unfortunately, it's worse, but moving in the
> > : right direction.
> > :
> > : Suspend:
> > : - Display backlight still turns on and remains on upon suspend. Video
> > :   does not blank, but loses power so display "rots" over a period of at
> > :   least minutes. (This is unchanged.) hw.acpi.video show correct values,
> > :   but fails to change them. DPMS blanking does blank the display but
> > :   does not turn off back-light.
> > :
> > : - hw.acpi.sleep_delay is now ignored, but the disk no longer does an
> > :   instant shutdown without flushing cache, so this is OK.
> > :
> > : - Suspend LED turns on. (Unchanged.)
> > :
> > : Resume:
> > : - I stop receiving interrupts on irq11 which handles much of my
> > :   system. This includes sound, CardBus, USB and network. This is the
> > :   big issue as the machine is now pretty useless.
> > :
> > : Unfortunately, this loss of irq11 makes further testing almost
> > : impossible. To further confuse things, interrupts continue for a
> > : seemingly random time of up to several minutes after the restore and
> > : then stop. This last part has me totally baffled, but maybe someone has
> > : some idea why this is happening. Non-irq11 devices (mouse, keyboard,
> > : clocks, ata controllers) continue to work.
> > :
> > : Anything you would like me to try?
> >
> > While my patches will make it better, more extensive changes to the
> > power code will be necessary to make it work perfectly.  Nate has been
> > taking the lead in this area.
> >
> > Why don't you try
> >
> > 	hw.pci.do_powerstates=1
> >

It does help (though it's hw.pci.do_powerstate=1). This has fixed the
problem of losing irq11. Now I am operational after resume. 

USB seems to be working (untested). Video is fine.

Sound is still not working correctly. It runs at native speed (about
52K) after resume which makes things run a bit fast and breaks playing
live streams. Attempts to use the sysctl to set the speed don't work. I
already have a PR open on this.

Bottom line is that things are a whole lot better. Suspend/resume is
usable if not practical. Remaining big problems are the display which
won't turn off (and turns back on if already off) and the sound. 

Sound is important on this system as I use it to participate in H.323
conferences with gnomemeeting.

All in all I am very happy with the progress on this. Warner's PCI
patches are a huge improvement. The sound problem is probably a driver
issue. I plan on building a kernel without sound support and load the
modules. I hope that I can unload and load the module after a suspend and
get sound working correctly. Yeah, it's a hack, but a livable one.

This only leaves the display and I fear that this is an IBM specific
issue. I hope that the work Nate is doing will fix it. Leaving the
screen on while suspended sort of defeats the purpose. :-(

Thanks to both of you for all of your work on this.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman_at_es.net			Phone: +1 510 486-8634