On Thursday, July 05, 2012, Alan Stern wrote: > On Thu, 5 Jul 2012, Bjorn Helgaas wrote: > > > I wish we knew more about what's really going on here. I looked > > through the bug reports AceLan dug up, and I don't get the feeling > > that anybody really has a grand unified theory about why Windows works > > but Linux doesn't. But I'm willing to apply one of these patches if > > you and/or Alan sign off on it. > > His description seems to make sense, even if it may not be complete. > > Windows sets the COMMAND register to 0 before suspending, so it doesn't > trigger the BIOS bus. Linux doesn't, so the BIOS tries to quiesce the > EHCI controller. This involves doing various MMIO accesses, which of > course don't work if the controller is already in D3. > > For obvious reasons, I'm in favor of my two-line change over AceLan's > new PCI quirk. So far there have been positive responses from a few > volunteers testing the patch. The two-liner is good enough, I think, and tested. We can always add a quirk based on it in the future. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
