On Tue, Apr 10, 2007 at 04:57:23PM -0500, Kim Phillips wrote: > also adds RX & TX delay bits to help boards with clock skew problems.
This doesn't make sense at all. RGMII specifies that clock and data are generated simultaneously. The necessary 1.5-2ns of clock delay is either achieved by routing the RGMII clock net to have that amount of skew, or by programming the RGMII receiver to add that amount of clock delay internally. So, boards that have 'clock skew problems' should have RX & TX delay turned OFF. Boards that route the clock nets without any skew should have RX & TX delay turned on. Your patch unconditionally enables clock delay in the 88e1111, which only makes sense if the RGMII data and clock nets are routed to have the approximate same amount of delay. Which means that it is entirely board-specific whether this should be enabled or not. If you enable the 88e1111 internal RX/TX clock delay feature on a board that also routes the RGMII clock nets to have the appropriate amount of skew, things are likely to break entirely. > [...] > + > + temp |= (MII_M1111_RX_DELAY | MII_M1111_TX_DELAY); Enabling this unconditionally is just wrong. I.e. the patch is wrong, and the description is wrong too. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
