On 8/4/2025 4:39 PM, Bjorn Helgaas wrote: > Drop a few of the subject line prefixes and mention something about > sysfs. This has nothing to do with portdrv. Following sibling "port > service drivers," I guess the prefix would be something like > "PCI/CXL:" or "PCI/CXL_ISO:" Will do. > > On Wed, Jul 30, 2025 at 04:47:15PM -0500, Ben Cheatham wrote: >> Add functions to enable programming the CXL.mem transaction timeout >> range, if supported. Add a sysfs attribute to the "cxl_isolation" group >> to allow programming the timeout from userspace. > > Include a sample path with at least the last 2-3 components. Maybe > even an example, e.g., > > # echo B2 > /sys/.../cxl_isolation/timeout_range > > Probably also some doc in Documentation/ABI/testing/? I'll add it to the commit message and make an entry under Documentation. > >> The attribute can take either the CXL spec-defined hex value for the >> associated timeout range (CXL 3.2 8.2.4.24.2 field 3:0) or a >> string with the range. The range string is formatted as the range letter >> in uppercase or lowercase, with an optional "2" to specify the second >> range in the aforementioned spec ref. >> >> For example, to program the port with a timeout of 65ms to 210ms (range B) >> the following strings could be specified: "b2"/"B2". Picking the first >> portion of range B (16ms to 55ms) would be: "b"/"B". > > What's the value of accepting either upper- or lower-case? It doubles > the size of ranges[], and I think timeout_range_show() always shows > the lower-case one. The spec uses upper-case. > Just ease of use. I'll restrict it to uppercase to match the spec (unless anyone has a strong opinion otherwise). Thanks, Ben
