Subject: Re: [PATCH 0/2] i.MX GPC DMA warning fixes

From: Shawn Guo <[email-masked]>
Date: Sun, 6 Oct 2019 10:06:42 +0800

On Fri, Sep 06, 2019 at 12:33:59PM +0200, Lucas Stach wrote:
> Hi all,
> 
> those two patches get rid of an annoying boot warning on all i.MX6+
> devices, as the generic OF DMA code tries to forcefully configure the
> DMA capabilities for the virtual GPX power domain devices, which will
> never do any DMA.
> 
> This solution isn't the most elegant, as we are making up a 0 DMA mask
> to silence the warning instead of skipping the DMA configuration
> completely. A previous submission of this change for just the GPC v1 [1]
> was shot down for this reason. But then we haven't made any progress in
> fixing this in a better way, as other systems depend on the forceful
> OF DMA configuration to work correctly. So we are stuck between a rock
> and a hard place here.
> 
> IMHO we should accept the slight uglyness of this solution in order to
> get rid of the warning now, as it is confusing users into thinking their
> kernel configuration or system setup is faulty, while everything is
> perfectly in order.
> 
> Regards,
> Lucas
> 
> [1] https://patchwork.kernel.org/patch/10621589/
> 
> Lucas Stach (2):
>   soc: imx: gpc: set DMA mask for PD platform devices
>   soc: imx: gpcv2: set DMA mask for PD platform devices

Please copy Arnd for comments.

Shawn

> 
>  drivers/soc/imx/gpc.c   | 1 +
>  drivers/soc/imx/gpcv2.c | 1 +
>  2 files changed, 2 insertions(+)
> 
> -- 
> 2.20.1
> 

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