17/07/2020 17:11, Slava Ovsiienko: > From: Thomas Monjalon <tho...@monjalon.net> > > 17/07/2020 16:28, Viacheslav Ovsiienko: > > > The dedicated MLX5_CMD_OP_ACCESS_REGISTER_USER opcode must be > > used to > > > read hardware register content from unprotected mode. > > > > Otherwise? What was broken? > > Otherwise the MLX5_CMD_OP_ACCESS_REGISTER was used, it returned EINVAL > and register value was not read. It was supposed to enable ACCESS_REGISTER > operation from user mode in kernel driver to read registers, but eventually > it was replaced with ACCESS_REGISTER_USER dedicated operation. > > mlx5 PMD does not rely on this feature strongly, if register reading fails > it deduces the timestamp mode from reported timestamp counter > frequency.
OK I think some of these explanations deserve to be in the commit log.
