On Mon, 31 Mar 2014 20:23:36 +0000 Stuart Yoder <stuart.yoder@xxxxxxxxxxxxx> wrote: > > From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > > Sent: Monday, March 31, 2014 2:47 PM > > > > On Mon, Mar 31, 2014 at 06:47:51PM +0000, Stuart Yoder wrote: > > > I also, was at the point where I thought we should perhaps just > > > go with current mechanisms and implement new_id for the platform > > > bus...but Greg's recent response is 'platform devices suck' and it > > sounds > > > like he would reject a new_id patch for the platform bus. So it kind > > > of feels like we are stuck. > > > > ids mean nothing in the platform device model, so having a new_id file > > for them makes no sense. > > They don't have IDs like PCI, but platform drivers have to match on > something. Platform device match tables are based on compatible strings. > > Example from Freescale DMA driver: > static const struct of_device_id fsldma_of_ids[] = { > { .compatible = "fsl,elo3-dma", }, > { .compatible = "fsl,eloplus-dma", }, > { .compatible = "fsl,elo-dma", }, > {} > }; > > The process of unbinding, setting a new_id, and binding to vfio would work > just like PCI: > > echo ffe101300.dma > /sys/bus/platform/devices/ffe101300.dma/driver/unbind > echo fsl,eloplus-dma > /sys/bus/platform/drivers/vfio-platform/new_id In platform device land, we don't want to pursue the new_id/match-by-compatible methodology: we know exactly which specific device (not device types) we want bound to which driver, so we just want to be able to simply: echo fff51000.ethernet | sudo tee -a /sys/bus/platform/devices/fff51000.ethernet/driver/unbind echo fff51000.ethernet | sudo tee -a /sys/bus/platform/drivers/vfio-platform/bind and not get involved with how PCI "doesn't simply do that," independent of autoprobe/hotplug. Kim -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
