Messages in this thread | | | Date | Thu, 10 Jul 2014 12:53:48 -0600 (MDT) | From | Keith Busch <> | Subject | Re: [RFC PATCH] Let device drivers disable msi on shutdown |
| |
On Thu, 10 Jul 2014, Bjorn Helgaas wrote: > [+cc LKML, Greg KH for driver core async shutdown question] > On Tue, Jun 24, 2014 at 10:48:57AM -0600, Keith Busch wrote: >> To provide context why I want to do this asynchronously, NVM-Express has >> one PCI device per controller, of which there could be dozens in a system, >> and each one may take many seconds (I've heard over ten in some cases) >> to safely shutdown. > > I don't see anything in device_shutdown() that would wait for this > sort of asynchronous shutdown to complete. So how do we know it's > finished before we turn off the power, reset, kexec, etc.? > > If we need to do asynchronous shutdown, it seems like we need some > sort of driver core infrastructure to manage that.
Yes, good point! To address that, I did submit this patch:
http://lists.infradead.org/pipermail/linux-nvme/2014-May/000827.html
I need to fix the EXPORT_SYMBOL_GPL usage for a v2, but before that, I wan't to know the reason the driver can't use MSIx in an async shutdown shutdown, and came to the patch mentioned above.
I'd originally had the async shutdown use legacy interrupts, but I know some NVMe devices do not support legacy, so can't use my original proposal. If I can't rely on MSI/MSI-x being enabled in an async shutdown, then I have to add polling, which I suppose we can live with.
| |