[U-Boot] [PATCH 0/2] Add fix for Pine64 gigabit throughput issues

[André Przywara]

Hi,

thanks for picking this up!

(CC:ing Icenowy, who was engaged in a Linux fix for this issue last year
[2][3]. It's Chinese New Year though, so not sure how quickly she will
answer).

On 14/02/18 23:02, kevans at FreeBSD.org wrote:
> The Pine64 has a known issue on gigabit links (see [1]); some boards suffer
> significant packet loss on Gigabit links.

Do you have a faulty board at hand? What is the actual effect in U-Boot?
IIRC the bug "just" causes a slower connection in Gigabit mode, I am not
sure we care so much in U-Boot? Or is it actually packages dropped,
which is much more annoying without TCP covering up for this?

> This patch sets the magical bits
> in CONFREG on the RTL8211E PHY to turn off the internal delay and do some other
> undocumented stuff.

So if I remember the discussion correctly, this workaround affects the
performance of the "good" boards. Have you checked this?
There was a discussion last year [2][3] about how to fix this in Linux,
which definitely involved some DT property (ideally in the PHY node).
This would allow people to turn this on and off depending on their
particular board.
I am not sure this discussion lead anywhere, though, it might be a good
idea to warm this up again.

Cheers,
Andre.

[2] https://marc.info/?l=devicetree&m=149281711105621
[3] https://marc.info/?l=linux-netdev&m=150337466923103

> [1] https://forum.pine64.org/showthread.php?tid=835&pid=19704#pid19704
> 
> Kyle Evans (2):
>   net: phy: Add PHY_RTL8211E_PINE64_GIGABIT_FIX for realtek phys
>   Configs: Use the newly added PHY_RTL8211E_PINE64_GIGABIT_FIX
> 
>  configs/pine64_plus_defconfig |  2 ++
>  drivers/net/phy/Kconfig       | 10 ++++++++++
>  drivers/net/phy/realtek.c     | 34 ++++++++++++++++++++++++++++++++++
>  3 files changed, 46 insertions(+)
>