On Thu, 10 Oct 2024 17:11:21 +0200 Til Kaiser wrote: > I noticed on our dual-port 100G ConnectX-4 cards (MT27700 Family) > running Linux Kernel version 6.6.56 and the latest ConnectX-4 firmware > version 12.28.2302 that we do not have a sysfs hwmon entry for reading > temperature values. > When running Kernel version 6.6.32, the hwmon entry is there again, and > I can read the temperature values of those cards. > Strangely, this problem doesn't occur on our ConnectX-4 Lx cards > (MT27710 Family), regardless of which Kernel version I use. > > I looked into the mlx5 core driver and noticed that it is checking the > MCAM register here: > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/net/ethernet/mellanox/mlx5/core/hwmon.c?h=v6.6.56#n380. > When I removed that check, the hwmon entry reappeared again. > > Looking into recent mlx5 commits regarding this MCAM register, I found > this commit: > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.6.56&id=fb035aa9a3f8fd327ab83b15a94929d2b9045995. > When I reverted this commit, the hwmon entry also reappeared again. > > I also found a firmware bug fix regarding that register inside the > ConnectX-4 Lx bug fix history here (Ref. 2339971): > https://docs.nvidia.com/networking/display/connectx4lxfirmwarev14321900/bug+fixes+history. > I couldn't find such a firmware fix for the non-Lx ConnectX-4 cards. So, > I'm unsure whether this might be a mlx5 driver or firmware issue. Hi, any word on this? Sounds like a fairly straightforward problem.
