[LEDE-DEV] [PATCH v2] imx6: fix pcie scanning on boot

[Koen Vandeputte]

3rd time's the charm :)  .. without html ..

>
>>     >
>>
>>     Hi Koen,
>>
>>     Thanks for this info!
>>
>>     Have you asked the linux-pci group about this? I'm curious what the
>>     patch to 4.9.71 was trying to do and if this is the proper place to
>>     fix this. I assume if we set that value in the bootloader it
>>     would get
>>     reset when the kernel does a PCI reset.
>>
>>     It seems like every couple of months there is some upstream breakage
>>     dealing with the i.MX6 and a PCIe switch :(
>>
>>     Regards,
>>
>>     Tim
>>
>
> Hi Tim,
>
> After this quick fix, Ive investigated this deeper.
>
> It seems not only imx6 was affected but all platforms using dwc for pcie.
> meanwhile, a definitive fix was submitted upstream towards the pci guys:
> https://patchwork.kernel.org/patch/10163363/
>
>
> The patch causing this actually makes sense:
> It enforces setting all port params to be set correctly according to 
> pcie spec.
>
> Separate backports are needed for 4.9 and older LTS kernels as the dwc 
> init code got moved.
> In 4.9 the backport will actually fix enumeration behind bridges.
> in 4.4 and older, no functional behaviour changes, but the nasty 
> warnings and errors are gone during boot.
>
> it is correct that setting this in bootloader doesnt affect the kernel 
> which resets the bus and reinits it completely.
> Just to ensure both are correct, Ive also submitted a fix to uboot 
> (imx6 only)
> http://git.denx.de/?p=u-boot.git;a=commit;h=f57263ee9bb8b5d9f39b48d09d21114c9dbb6a02
>
>
> Kind regards,
>
> Koen