Re: [PATCH 1/1] ARM: dts: imx6qdl: Add reserved memory area for CMA memory

[Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>]

Am Mittwoch, 28. August 2024, 09:49:36 CEST schrieb Alexander Stein:
> Am Dienstag, 27. August 2024, 16:24:58 CEST schrieb Alexander Stein:
> > Default CMA size is too small for HDMI output and VPU usage. Increase the
> > default size by providing a CMA memory area.
> > 
> > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> > ---
> > Smallest RAM variant has 512MiB.
> > 
> >  arch/arm/boot/dts/nxp/imx/imx6qdl-mba6.dtsi | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> > 
> > diff --git a/arch/arm/boot/dts/nxp/imx/imx6qdl-mba6.dtsi b/arch/arm/boot/dts/nxp/imx/imx6qdl-mba6.dtsi
> > index d03f7065ddfd7..8ba3ec27bee07 100644
> > --- a/arch/arm/boot/dts/nxp/imx/imx6qdl-mba6.dtsi
> > +++ b/arch/arm/boot/dts/nxp/imx/imx6qdl-mba6.dtsi
> > @@ -106,6 +106,20 @@ reg_vcc3v3_audio: regulator-vcc3v3-audio {
> >  		vin-supply = <&reg_mba6_3p3v>;
> >  	};
> >  
> > +	reserved-memory {
> > +		#address-cells = <1>;
> > +		#size-cells = <1>;
> > +		ranges;
> > +
> > +		linux,cma {
> > +			compatible = "shared-dma-pool";
> > +			reusable;
> > +			size = <0x14000000>;
> > +			alloc-ranges = <0x10000000 0x20000000>;
> > +			linux,cma-default;
> > +		};
> > +	};
> > +
> 
> Please do not merge yet.
> I just noticed that this breaks mmap'ed fbdev usage. It only works when CMA
> area is in HighMem.

Okay, now that commit 5a498d4d06d6d ("drm/fbdev-dma: Only install deferred
I/O if necessary") has been applied, the mentioned problem is gone.
This patch can be applied if there are no concerns.

Best regards,
Alexander
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