18c2ecf20Sopenharmony_ciWhat: /sys/bus/nd/devices/regionX/nfit/ecc_unit_size 28c2ecf20Sopenharmony_ciDate: Aug, 2017 38c2ecf20Sopenharmony_ciKernelVersion: v4.14 (Removed v4.18) 48c2ecf20Sopenharmony_ciContact: linux-nvdimm@lists.01.org 58c2ecf20Sopenharmony_ciDescription: 68c2ecf20Sopenharmony_ci (RO) Size of a write request to a DIMM that will not incur a 78c2ecf20Sopenharmony_ci read-modify-write cycle at the memory controller. 88c2ecf20Sopenharmony_ci 98c2ecf20Sopenharmony_ci When the nfit driver initializes it runs an ARS (Address Range 108c2ecf20Sopenharmony_ci Scrub) operation across every pmem range. Part of that process 118c2ecf20Sopenharmony_ci involves determining the ARS capabilities of a given address 128c2ecf20Sopenharmony_ci range. One of the capabilities that is reported is the 'Clear 138c2ecf20Sopenharmony_ci Uncorrectable Error Range Length Unit Size' (see: ACPI 6.2 148c2ecf20Sopenharmony_ci section 9.20.7.4 Function Index 1 - Query ARS Capabilities). 158c2ecf20Sopenharmony_ci This property indicates the boundary at which the NVDIMM may 168c2ecf20Sopenharmony_ci need to perform read-modify-write cycles to maintain ECC (Error 178c2ecf20Sopenharmony_ci Correcting Code) blocks. 18