0357d5cab8
The E822 devices support an extended "vernier" calibration which enables higher precision timestamps by accounting for delays in the PHY, and compensating for them. These delays are measured by hardware as part of its vernier calibration logic. The driver currently starts the PHY in "bypass" mode which skips the compensation. Then it later attempts to switch from bypass to vernier. This unfortunately does not work as expected. Instead of properly compensating for the delays, the hardware continues operating in bypass without the improved precision expected. Because we cannot dynamically switch between bypass and vernier mode, refactor the driver to always operate in vernier mode. This has a slight downside: Tx timestamp and Rx timestamp requests that occur as the very first packet set after link up will not complete properly and may be reported to applications as missing timestamps. This occurs frequently in test environments where traffic is light or targeted specifically at testing PTP. However, in practice most environments will have transmitted or received some data over the network before such initial requests are made. Signed-off-by: Milena Olech <milena.olech@intel.com> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.