[FS#670] whr-1166d gigabit port not working

[LEDE Bugs]

The following task has a new comment added:

FS#670 - whr-1166d gigabit port not working
User who did this - Robin Panda (andapanda)

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Workaround is as simple as reverting [[https://dev.openwrt.org/changeset/47346/trunk/target/linux/ramips/mt7620/config-3.18|this post-CC change.]] Just add a #. So either the IP1001 phy driver is broken, or it's changing something that is correct by default or bootloader setup to something incorrect for this router.

Why was the driver added in the first place? It works fine with the generic driver. [[https://lists.openwrt.org/pipermail/openwrt-devel/2015-October/036807.html|A post on the OpenWRT mailing list]] indicates the only gain is APS support, but [[http://www.icplus.com.tw/data/datasheet/ip1001_ds_r17_20101013.pdf|page 24 on the datasheet]] says it's already enabled by default.

In the icplus.c init, in addition to setting APS, it also appears to set the RGMII delay mode. This is also not done by the generic driver. Datasheet page 37 says these are initialized by pins at poweron. Overwriting this with the wrong value could explain the problem.

If that's the problem, then a better fix could be setting phy-mode to rgmii-id or rgmii-rxid in the dts. Unfortunately this probably will not work because I can not find anything similar to [[https://patchwork.kernel.org/patch/9152099/|this patch.]] The comments there seem to support my theory. Another fix could be making icplus.c respect the hardware configuration, but this would affect many more devices. The bad software design is probably to make up for bad hardware design somewhere else on some other architecture.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=670#comment2811