Kok, Auke wrote: > Eric W. Biederman wrote: >> "Kok, Auke" <auke-jan.h.kok at intel.com> writes: >> >>> Ingo Molnar wrote: >>>> * Kok, Auke <auke-jan.h.kok at intel.com> wrote: >>>> >>>>>>> BUG: at drivers/pci/msi.c:611 pci_enable_msi() >>>>>> I would poke Eric Biederman(sp?) about this one. Maybe its even solved by >>>>>> the MSI-enable-related patch he posted in the past 24-48 hours. >>>>> I tried the 3-patch series "[PATCH 0/3] Basic msi bug fixes.." and they fix >>>>> this problem for me. Were you expecting the OOPS in the first place? [...] >>>> the bug was the warning message (a WARN_ON()) above - not an oops. So that >>>> warning message is gone in your testing? >>> yes. >> Sorry for the slow delay. I was out of town for my brothers wedding the last few >> days. >> >> I wasn't exactly expecting the WARN_ON to trigger. What I fixed was >> an inconsistency in handling our state bits. Fixing that >> inconsistency appears to have fixed the e1000 usage scenario mostly by >> accident. >> >> The basic issue is that pci_save_state saves the current msi state >> along with other registers, and then the e1000 driver goes and >> disables the msi irq after we have saved the irq state as on. >> >> My code notices that the msi irq was disabled before restore time, so >> it skips the restore. However we now have a leak of the msi saved cap >> because we are not freeing it. >> >> This leaves with some basic questions. >> - Does it make sense for suspend/resume methods to request/free irqs? >> - Does it make sense for suspend/resume methods to allocate/free msi irqs? >> - Do we want pci_save/restore_cap to save/restore msi state? >> >> The path of least resistance is to just free the extra state and we >> are good. I'm just not quite certain that is sane and it has been a >> long day. > > we used to have a lengthy e1000_pci_save|restore_state in our code, which is now > gone, so I'm all for that. A separate pci_save_pxie|msi(x)_state for every > driver seems completely unnecessary. I can't think of a use case where > saving+restoring everything hurts. That's what you want I presume. > > We currently free all irq's and msi before going into suspend in e1000, and I > think that is probably a good thing, somehow I can think of bad things happening > if we dont, but I admit that I haven't tried it without alloc/free. We do this > in e100 as well and it works. > > Another motivation would be to leave this up to the driver: if the driver > chooses to free/alloc interrupts because it makes sense, you probably would want > to keep that choice available. Devices that don't need this can skip the > alloc/free, but leave the choice open for others. ah, looking at the code in e1000 we do: _suspend: pci_save_state(); free_irq() _resume: pci_restore_state(); alloc_irq(); I suppose that's not good either, and the major cause of the warning in the first place. Maybe I can rollback your latest patches and try to fix that mess by postponing the pci_save_state until after we free'd the irq's. Auke
