Hi Boris, Please find reply inline. >-----Original Message----- >From: Borislav Petkov <bp@xxxxxxxxx> >Sent: 14 November 2024 13:33 >To: Shiju Jose <shiju.jose@xxxxxxxxxx> >Cc: linux-edac@xxxxxxxxxxxxxxx; linux-cxl@xxxxxxxxxxxxxxx; linux- >acpi@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >tony.luck@xxxxxxxxx; rafael@xxxxxxxxxx; lenb@xxxxxxxxxx; >mchehab@xxxxxxxxxx; dan.j.williams@xxxxxxxxx; dave@xxxxxxxxxxxx; Jonathan >Cameron <jonathan.cameron@xxxxxxxxxx>; gregkh@xxxxxxxxxxxxxxxxxxx; >sudeep.holla@xxxxxxx; jassisinghbrar@xxxxxxxxx; dave.jiang@xxxxxxxxx; >alison.schofield@xxxxxxxxx; vishal.l.verma@xxxxxxxxx; ira.weiny@xxxxxxxxx; >david@xxxxxxxxxx; Vilas.Sridharan@xxxxxxx; leo.duran@xxxxxxx; >Yazen.Ghannam@xxxxxxx; rientjes@xxxxxxxxxx; jiaqiyan@xxxxxxxxxx; >Jon.Grimm@xxxxxxx; dave.hansen@xxxxxxxxxxxxxxx; >naoya.horiguchi@xxxxxxx; james.morse@xxxxxxx; jthoughton@xxxxxxxxxx; >somasundaram.a@xxxxxxx; erdemaktas@xxxxxxxxxx; pgonda@xxxxxxxxxx; >duenwen@xxxxxxxxxx; gthelen@xxxxxxxxxx; >wschwartz@xxxxxxxxxxxxxxxxxxx; dferguson@xxxxxxxxxxxxxxxxxxx; >wbs@xxxxxxxxxxxxxxxxxxxxxx; nifan.cxl@xxxxxxxxx; tanxiaofei ><tanxiaofei@xxxxxxxxxx>; Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>; Roberto >Sassu <roberto.sassu@xxxxxxxxxx>; kangkang.shen@xxxxxxxxxxxxx; >wanghuiqiang <wanghuiqiang@xxxxxxxxxx>; Linuxarm ><linuxarm@xxxxxxxxxx> >Subject: Re: [PATCH v15 11/15] EDAC: Add memory repair control feature > >On Mon, Nov 11, 2024 at 04:54:48PM +0000, Shiju Jose wrote: >> Presently, 0 (soft memory repair) and 1 (hard memory repair), depends >> on which mode/s a memory device is supported. > >What if the device supports more than one mode? > >> However for CXL memory sparing feature, the persistent mode is >> configurable at runtime for a memory sparing instance, thus both soft and >hard sparing are supported. >> Example given for CXL memory sparing feature in >> Documentation/edac/memory_repair.rst, >> root@localhost:~# cat >> /sys/bus/edac/devices/cxl_mem0/mem_repair1/persist_mode_avail >> 0,1 > >Ok, and how is the user supposed to know what those mean? Print in string format?, may be as 'persist'/'volatile'? > >> Kernel sysfs doc mentioned about array of values as follows, though not seen >much examples. >> https://docs.kernel.org/filesystems/sysfs.html >> "Attributes should be ASCII text files, preferably with only one value >> per file. It is noted that it may not be efficient to contain only one >> value per file, so it is socially acceptable to express an array of values of the >same type." > >True story. Ok, so there's an exception to that rule. > >> The values of these attributes are specific to device and portion of the memory >to repair. >> For example, In CXL repair features, >> CXL memory device identifies a failure on a memory component, device >> provides the corresponding values of the attributes (DPA, channel, >> rank, nibble mask, bank group, bank, row, column or sub-channel etc) in an >event record to the host and to the userspace in the corresponding trace event. >> Userspace shall use these values for the query resource availability and repair >operations. > >I don't think you're answering my question. Lemme try again: > >I am on a machine with such an interface. I do > >echo 0xdeadbeef > /sys/devices... >-EINVAL > >echo 0xface > ... >-EINVAL > >How do I know what the allowed ranges are? I am fine with adding the support for expose the ranges of these, but makes more sense to do it when a driver surfaces that can do it. I will use the DPA for CXL features as an example of how it would be done and it's the one is supported now. >> This will work for the CXL PPR feature where the result of the query [...] >-- >Regards/Gruss, > Boris. > >https://people.kernel.org/tglx/notes-about-netiquette Thanks, Shiju
