Hi David, Hi Florian, We use a Micrel KSZ8041NL and we observe sometimes continuous RX errors (PHY's RXER counter is continuously incrementing, activity LED blinks and no communication is possible). It seems that only some PHY's are affected (3-4%) and only in certain temperature ranges (the PHY I can reproduce the issue here shows the problem ~30°C). We could narrow the issue down, and realized that the problem only appears after the PHY has been in power down mode. Since Linux calls suspend/resume when attaching/detaching the PHY, a simple ifup/ifdown bascially can trigger the issue.
Currently, the wakeup sequence writes the following registers 0x8000 to 0x00 (phy_attach_direct -> phy_init_hw -> genphy_soft_reset) 0x3000 to 0x00 (phy_attach_direct -> genphy_resume) I am not sure if this sequence is really ok. It seems to me that genphy_soft_reset clears the power down bit already, which makes genphy_resume somewhat useless. However, altering the behavior of genphy_soft_reset to not clear the power down bit (yet) did not resolve the issue. Is clearing the power down bit and generating the reset in one go intended? I checked the datasheet, and did not found particular information about the "resume" sequence... -- Stefan
