On Sat, Apr 18, 2009 at 03:59:18PM +0200, Rafael J. Wysocki wrote: > On Saturday 18 April 2009, Rafael J. Wysocki wrote: > > On Saturday 18 April 2009, Russell King wrote: > > > Some platforms need to talk via I2C to power control devices during > > > the suspend method. Currently, they do this via the platform PM ops > > > prepare callback, relying on the I2C driver being hooked into the > > > 'late' suspend method, and hence being shut down _after_ the prepare > > > callback. > > > > Well, I was not aware of this dependency and it seems quite unusual for a > > platform to depend on a driver like this. > > > > > However, as of the above commit, the ordering is changed such that > > > platforms don't get notified of suspends until after all devices are > > > well and truely shut down. > > > > > > This can't work, and actively breaks some platforms. > > > > Sorry for that. > > > > The patchset in question had been discussed quite extensively before it was > > merged and it's a pity none of the people caring for the affected platforms > > took part in those discussions. That would allow us to avoid the breakage. > > > > > Please come up with another solution for your PCI problems, > > > > I don't think this is possible, sorry. > > > > > or provide alternative equivalent functionality where the platform code is > > > notified of the PM event prior to the late suspend callback being issued. > > > > There is the .begin() callback that could be used, but if you need the > > platform to be notified _just_ prior to the late suspend callback, then the > > only thing I can think of at the moment is the appended patch. > > > > It shouldn't break anything in theory, because the majority of drivers put > > their devices into low power states in the "regular" suspend callbacks anyway. > > Still, if it turns out to break anything, we'll have to think of an alternative > approach. > > Which platforms exactly are affected? The one I've maintained since 2.6.9 and am just sending out the initial bits for final review. (It's taking a long time to get it out there because I can only spend very little time on it, and it keeps getting broken - ALSA, SCSI and now PM have all broken it in the last couple of months.) -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
