Re: [PATCH 0/3] PCI: rockchip: 5.0 GT/s speed may be dangerous

[Shawn Lin <shawn.lin@rock-chips.com>]

Hi Geraldo,

在 2025/11/15 星期六 17:10, Geraldo Nascimento 写道:
> In recent interactions with Shawn Lin from Rockchip it came to my
> attention there's an unknown errata regarding 5.0 GT/s operational
> speed of their PCIe core. According to Shawn there's grave danger
> even if the odds are low. To contain any damage, let's cover the
> remaining corner-cases where the default would lead to 5.0 GT/s
> operation as well as add a comment to Root Complex driver core,
> documenting this danger.
> 

I'm not sure just adding a warn would be a good choice. Could we totally
force to use gen1 and add a warn if trying to use Gen2.

Meanwhile amend the commit message to add a reference
of RK3399 official datesheet[1] which says PCIe on RK3399 should only
support 2.5GT/s?


[1]https://opensource.rock-chips.com/images/d/d7/Rockchip_RK3399_Datasheet_V2.1-20200323.pdf

> Geraldo Nascimento (3):
>    PCI: rockchip: warn of danger of 5.0 GT/s speeds
>    PCI: rockchip-host: comment danger of 5.0 GT/s speed
>    arm64: dts: rockchip: drop max-link-speed = <2> in helios64 PCIe
> 
>   arch/arm64/boot/dts/rockchip/rk3399-kobol-helios64.dts | 1 -
>   drivers/pci/controller/pcie-rockchip-host.c            | 5 +++++
>   drivers/pci/controller/pcie-rockchip.c                 | 8 ++++++--
>   3 files changed, 11 insertions(+), 3 deletions(-)
>