2014-02-05 David Laight <David.Laight@xxxxxxxxxx>: > From: Florian Fainelli >> It would be good to explain exactly how your hardware is broken >> exactly. I really do not think that such a fine-grained setting where >> you could disable, e.g: 100BaseT_Full, but allow 100BaseT_Half to >> remain usable makes that much sense. In general, Gigabit might be >> badly broken, but 100 and 10Mbits/sec should work fine. How about the >> MASTER-SLAVE bit, is overriding it really required? > > There are plenty of systems out there where you'd want to disable > either HDX or FDX modes. > The MAC unit has to know whether the PHY is in HDX or FDX in order > to work properly. Many do not need to know the speed - since the > PHY is responsible for the tx/rx fifo clock. > Getting the negotiated speed out of the PHY can be difficult, while > the ANAR can easily be set. > Unfortunately it is usually impossible to disable the 'fall-back' > 10M HDX. The problem that I have with that approach in general is that: - it bloats the code for a set of properties that are going to be used by hopefully a few percentage of the actual Device Trees out there - it puts no limits on what is acceptable/best-practice to be put in terms of configuration in the Device Tree, how about the 16x16 other register values out there which are standardized? - a PHY fixup should be registered based on the top-level compatible property for a given board where the specific PHY on a specific board is known to be broken - make things incredibly harder to debug than they are today I do acknowledge the need to have a solution to these problems, but this seems to duplicate existing mechanisms available (e.g: PHY fixups) without leveraging information that should be properly flagged in the Device Tree (board model, root-node compatible string etc...) to allow software to take corrective measures. -- Florian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
