[U-Boot] [PATCH 1/2] x86: baytrail: Fix unstable ACPI S3 resume

[Stefan Roese]

On 12.10.2017 14:07, Bin Meng wrote:
> It was observed that when booting a Ubuntu 16.04 kernel, doing ACPI
> S3 suspend/resume sometimes causes the Ubuntu kernel hang forever.
> The issue is however not reproduced with a kernel built from i386/
> x86_64 defconfig configuration.
> 
> The unstability is actually caused by unexpected interrupts being
> generated during the S3 resume. For some unknown reason, FSP (gold4)
> for BayTrail configures the GPIO DFX5 PAD to enable level interrupt
> (bit 24 and 25). As this pin keeps generating interrupts during an
> S3 resume, and there is no IRQ requester in the kernel to handle it,
> the kernel seems to hang and does not continue resuming.
> 
> Clear the mysterious interrupt bits for this pin.

Thanks for working on this. This must have been very tough to debug
and fix.

> Reported-by: Stefan Roese <sr at denx.de>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>

Tested-by: Stefan Roese <sr at denx.de>
Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan