On 21/08/13 12:14PM, Bjorn Helgaas wrote: > [+cc Amey (working on PCI resets), linux-pci] > > On Fri, Aug 13, 2021 at 05:01:32PM +0000, Vikram Sethi wrote: > > Hi Dan, > > > > > -----Original Message----- > > > From: Dan Williams <dan.j.williams@xxxxxxxxx> > > > > > > On Wed, Aug 11, 2021 at 9:42 AM Chris Browy <cbrowy@xxxxxxxxxxxxxxxx> > > > wrote: > > > > > > /sys/bus/pci/devices/$device/reset is a method to trigger PCI > > > device reset, but I do not expect that will ever gain CXL specific > > > knowledge. > > > > > CXL reset may need some thought, specially for devices that don't > > expose FLR but do expose CXL reset (while former does not affect > > CXL.cache/mem, the latter wipes out CXL.cache/mem state in the > > device and there is discoverability as to whether or not memory > > contents can be cleared as part of CXL reset). We may need a way of > > triggering CXL reset from userspace, and if the existing > > /sys/bus/pci/devices/$device/reset won't have knowledge of CXL > > reset, there still should be a prioritized order in the kernel in > > which CXL reset is attempted before more drastic resets like SBR. > > IIRC CXL reset can also impact all functions that use CXL.cache/mem, > > but not legacy PCIe functions on the device which do not use > > CXL.cache/mem (there is discoverability as to which functions are > > not impacted by CXL reset). > > > > Thanks, > > Vikram We can add new reset method and expose it to userspace via new 'reset_method' sysfs attribute introduced in this series https://lore.kernel.org/linux-pci/20210805162917.3989-1-ameynarkhede03@xxxxxxxxx/ Thanks, Amey
