Dell - Internal Use - Confidential
> -----Original Message----- > From: Dan Williams [mailto:dan.j.willi...@intel.com] > Sent: Wednesday, March 29, 2017 1:13 PM > To: Lijun Pan <lijunpan2...@gmail.com> > Cc: linux-nvdimm@lists.01.org; Pan, Lijun <lijun_...@dell.com>; Hayes, > Stuart <stuart_ha...@dell.com> > Subject: Re: [PATCH v2] libndctl: add support for the MSFT family of DSM > functions > > On Sun, Mar 26, 2017 at 1:17 PM, Lijun Pan <lijunpan2...@gmail.com> wrote: > > From: Lijun Pan <lijun....@dell.com> > > > > This patch retrieves the health data from NVDIMM-N via > > the MSFT _DSM function[1], following JESD245A[2] standards. > > Now 'ndctl list --dimms --health --idle' could work > > on MSFT type NVDIMM-N, but limited to health_state, > > temperature_celsius, and life_used_percentage. > > Looks good, can you add sample output of: > > ndctl list --dimms --health --idle > Dan, Do you want me to put this sample output in the v3 patch's commit message? Output is something like, "health":{ "health_state":"ok", "temperature_celsius":193.750000, "life_used_percentage":1 } If the BIOS returns a value say 45.75, how can it be represented in (__u16) instead of using a 'double' type? I think the ((__u16) temp & 0x0FFC) already represents a temperature in 1/16 Celsius granularity. No need to multiple it by 16 again. Below I quote the section 7.8 of JESD245.pdf Bit 3 has a resolution of 1/2 Celsius, Bit 2 has a resolution of 1/4 Celsius, Bit 1 has 1/8 Celsius, but is reserved, so I assume it be zero, Bit 0 has 1/16 Celsius, but is reserved, so I assume it be zero. ((__u16) temp & 0x0FFC) will only get the bit11 - bit 0. This presents the 1/16 Celsius resolution, kind of left shifted 4 bits. So we don't need to do 'return CMD_MSFT_SMART(cmd)->temp * 16;' again. ==== = quotation starts ===== " Temperature measurement shall have a minimum resolution of 0.25 Celsius. Registers containing measured temperature value shall be 16-bits and report temperature as a 10-bit value based on the following definition. Table 3: Temperature value bit definition Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Bit9 Bit8 Reserved Reserved Reserved Reserved 128 64 32 16 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 8 4 2 1 0.5 0.25 Reserved Reserved Examples: A temperature value of 10.5 Celsius is represented as 0000000010101000b. A temperature value of 64.75 Celsius is represented as 0000010000001100b. " ==== quotation ends ======== Lijun > ...so users know what to expect. With that change and addressing > Linda's comment about the temperature multiplier I think we're good to > go. > > Also, if you want to add Microsoft-only health attributes we'll need > to add new "valid" flags beyond the current ND_SMART_*_VALID set. If > this goes beyond the current 32 "valid" flags that that > ndctl_cmd_smart_get_flags() returns we might need a new > ndctl_cmd_smart_get_flags2() call that returns an arbitrary bitmap of > valid flags. > > We'd also need to move those definitions to an ndctl local header. > Currently where they are defined now in ndctl.h is owned by the > kernel. We can cross this bridge later in a follow-on patch. I will do it on a follow-up patch later. Lijun _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
