On Wed, Dec 09, 2020 at 07:04:02PM +0000, John Garry wrote: > On 09/12/2020 18:32, Greg KH wrote: > > On Wed, Dec 02, 2020 at 06:36:56PM +0800, John Garry wrote: > > > Drivers for multi-queue platform devices may also want managed interrupts > > > for handling HW queue completion interrupts, so add support. > > > > Hi Greg, > > > Why would a platform device want all of this? Shouldn't such a device > > be on a "real" bus instead? > > For this HW version, the device is on the system bus, directly addressable > by the CPU. What do you mean by "system bus"? > Motivation is that I wanted to switch the HW completion queues to use > managed interrupts. Fair enough, seems like overkill for a "platform" bus though :) > > What in-kernel driver needs this complexity? I can't take new apis > > without a real user in the tree, sorry. > > It's in the final patch in the series https://lore.kernel.org/linux-scsi/1606905417-183214-1-git-send-email-john.garry@xxxxxxxxxx/T/#m0df7e7cd6f0819b99aaeb6b7f8939ef1e17b8a83. Ah, I missed that, I thought that was some high-speed scsi thing, not a tiny platform driver... > I don't anticipate a huge number of users of this API in future, as most > multi-queue devices are PCI devices; so we could do the work of this API in > the driver itself, but the preference was not to export genirq functions > like irq_update_affinity_desc() or irq_create_affinity_masks(), and rather > have a common helper in the core platform code. Ok, I'd like to have the irq maintainers/developers ack this before taking it in the driver core, as someone is going to have to maintain this crazy thing for forever if it gets merged. thanks, greg k-h
