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KSZ8851 errata sheet DS80000716D-page 4 Module 3 [1] states that,
when issuing a software power-down (PMECR[1:0] = 10) followed by a
power-on (PMECR[1:0] = 00), the receiver circuit can fail to start
properly preventing communication. The Transmitter will still send
data, but no data will be received.
The errata sheet also includes a workaround, which states that,
it is recommended that the software power-down feature not be used.
Implement that workaround and drop the entry into software power-down
mode. The ks8851_write_mac_addr() calls entry into normal power-on
mode at the very beginning of the function, therefore dropping the
second call to enter software power-down mode is sufficient here.
The ks8851_net_stop() can only be called after ks8851_net_start()
was already called, and ks8851_net_start() also makes the MAC enter
normal power-on mode, therefore it is also fine to drop the call to
enter software power-down mode from ks8851_net_stop().
This will lead to a slight increase in power consumption, but it also
fixes a sporadic reliability problem on at least KSZ8851-16MLL, which
is where the problem was reported and this fix was tested.
[1] https://ww1.microchip.com/downloads/en/DeviceDoc/80000716D.pdf
Fixes:
|
||
|---|---|---|
| .. | ||
| Kconfig | ||
| ks8842.c | ||
| ks8851_common.c | ||
| ks8851_par.c | ||
| ks8851_spi.c | ||
| ks8851.h | ||
| ksz884x.c | ||
| Makefile | ||