[U-Boot] [PATCH] ARM: mx6: Disable PCIe on SABRE Lite/Nitrogen6x

[Marek Vasut]

On Saturday, March 22, 2014 at 09:50:52 PM, Thierry Bultel wrote:
> When I communicated about the bug I had,
> and said that my temporary workaround was to disable the PCIe,
> my intention was not to make the suppression become a standard,
> and I believe it is a little bit frustrating for Marek.

It's not frustrating for me ;-)

> The AMOS820, based on the sabrelite/nitrogen has a PCIe slot on the main
> board,
> so there might be some interest of having the PCIe support enabled.

Do you have the PERST routed correctly and handled correctly ? If so, it does 
not matter whether or not you probed the PCIe bus in U-Boot , since toggling the 
PERST will cause Fundamental Reset (See [1]).

> To my mind, the bug is in the kernel I am using, it should be robust
> to the fact that PCIe has been formerly probed.

Freescale's 3.0.35 is crap, that's no news. If possible (read: you don't need 
GPU/VPU), use mainline.

> Wouldn't that be smarter to have the PCIe enabled or not,
> by an environment variable (defaulted to YES, and that the user could
> set to NO eventually for older kernels) ?
> Best regards

No, read [1] and probably the entire thread . For example [2] is also of 
interest here. If you soft-reset the system, your PCIe link will still be up 
from the previously running Linux instance (just like if it was started in U-
Boot) and you'll run into the same problem with the newly booted instance if 
Linux kernel.

So once again, did you correctly implement PERST so you can do FR properly ?

[1] http://lists.denx.de/pipermail/u-boot/2014-February/172496.html
[2] http://lists.denx.de/pipermail/u-boot/2014-February/172509.html

Best regards,
Marek Vasut