1. Patchew
  2. linux
  3. View series

[PATCH] arm64: dts: imx8mq: Set the correct gpu_ahb clock frequency

Sebastian Krzyszkowiak posted 1 patch 1 week, 6 days ago
There is a newer version of this series
arch/arm64/boot/dts/freescale/imx8mq.dtsi | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
[PATCH] arm64: dts: imx8mq: Set the correct gpu_ahb clock frequency
Posted by Sebastian Krzyszkowiak 1 week, 6 days ago 
According to i.MX 8M Quad Reference Manual, GPU_AHB_CLK_ROOT's maximum
frequency is 400MHz.

Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
---
 arch/arm64/boot/dts/freescale/imx8mq.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mq.dtsi b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
index 607962f807be..6a25e219832c 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
@@ -1632,7 +1632,7 @@ gpu: gpu@38000000 {
 			                         <&clk IMX8MQ_GPU_PLL_OUT>,
 			                         <&clk IMX8MQ_GPU_PLL>;
 			assigned-clock-rates = <800000000>, <800000000>,
-			                       <800000000>, <800000000>, <0>;
+			                       <800000000>, <400000000>, <0>;
 			power-domains = <&pgc_gpu>;
 		};
 

---
base-commit: 24d479d26b25bce5faea3ddd9fa8f3a6c3129ea7
change-id: 20260105-imx8mq-gpu-ahb-clock-139ba9ca9a6c

Best regards,
-- 
Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Re: [PATCH] arm64: dts: imx8mq: Set the correct gpu_ahb clock frequency
Posted by Fabio Estevam 1 week, 3 days ago 
On Sat, Jan 24, 2026 at 10:56 AM Sebastian Krzyszkowiak
<sebastian.krzyszkowiak@puri.sm> wrote:
>
> According to i.MX 8M Quad Reference Manual, GPU_AHB_CLK_ROOT's maximum
> frequency is 400MHz.
>
> Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>

Shouldn't this have a Fixes tag?
Re: [PATCH] arm64: dts: imx8mq: Set the correct gpu_ahb clock frequency
Posted by Frank Li 1 week, 4 days ago 
On Sat, Jan 24, 2026 at 02:55:48PM +0100, Sebastian Krzyszkowiak wrote:
> According to i.MX 8M Quad Reference Manual, GPU_AHB_CLK_ROOT's maximum
> frequency is 400MHz.

I checked datasheet

Nominal mode—the maximum
GPU frequency supported in
this mode is 800 MHz.

Does difference grade (industry vs consumer) impact max frequency?

Frank
>
> Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
> ---
>  arch/arm64/boot/dts/freescale/imx8mq.dtsi | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mq.dtsi b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> index 607962f807be..6a25e219832c 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> @@ -1632,7 +1632,7 @@ gpu: gpu@38000000 {
>  			                         <&clk IMX8MQ_GPU_PLL_OUT>,
>  			                         <&clk IMX8MQ_GPU_PLL>;
>  			assigned-clock-rates = <800000000>, <800000000>,
> -			                       <800000000>, <800000000>, <0>;
> +			                       <800000000>, <400000000>, <0>;
>  			power-domains = <&pgc_gpu>;
>  		};
>
>
> ---
> base-commit: 24d479d26b25bce5faea3ddd9fa8f3a6c3129ea7
> change-id: 20260105-imx8mq-gpu-ahb-clock-139ba9ca9a6c
>
> Best regards,
> --
> Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
>
Re: [PATCH] arm64: dts: imx8mq: Set the correct gpu_ahb clock frequency
Posted by Sebastian Krzyszkowiak 1 week, 4 days ago 
On poniedziałek, 26 stycznia 2026 19:14:55 czas środkowoeuropejski standardowy 
Frank Li wrote:
> On Sat, Jan 24, 2026 at 02:55:48PM +0100, Sebastian Krzyszkowiak wrote:
> > According to i.MX 8M Quad Reference Manual, GPU_AHB_CLK_ROOT's maximum
> > frequency is 400MHz.
> 
> I checked datasheet
> 
> Nominal mode—the maximum
> GPU frequency supported in
> this mode is 800 MHz.
> 
> Does difference grade (industry vs consumer) impact max frequency?

No. That sentence relates to GPU_SHADER_CLK_ROOT, which can go up to 1000 MHz, 
but requires "overdrive mode" (higher voltage) when above 800 MHz. It's set to 
800 MHz in the device tree at the moment.

This patch changes GPU_AHB_CLK_ROOT, which has absolute maximum of 400 MHz 
(see section 5.1.2 Table 5-1).

> Frank
> 
> > Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
> > ---
> > 
> >  arch/arm64/boot/dts/freescale/imx8mq.dtsi | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> > b/arch/arm64/boot/dts/freescale/imx8mq.dtsi index
> > 607962f807be..6a25e219832c 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> > +++ b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> > @@ -1632,7 +1632,7 @@ gpu: gpu@38000000 {
> > 
> >  			                         <&clk 
IMX8MQ_GPU_PLL_OUT>,
> >  			                         <&clk 
IMX8MQ_GPU_PLL>;
> >  			
> >  			assigned-clock-rates = <800000000>, 
<800000000>,
> > 
> > -			                       <800000000>, 
<800000000>, <0>;
> > +			                       <800000000>, 
<400000000>, <0>;
> > 
> >  			power-domains = <&pgc_gpu>;
> >  		
> >  		};
> > 
> > ---
> > base-commit: 24d479d26b25bce5faea3ddd9fa8f3a6c3129ea7
> > change-id: 20260105-imx8mq-gpu-ahb-clock-139ba9ca9a6c
> > 
> > Best regards,
> > --
> > Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Re: [PATCH] arm64: dts: imx8mq: Set the correct gpu_ahb clock frequency
Posted by Frank Li 1 week, 3 days ago 
On Mon, Jan 26, 2026 at 09:10:37PM +0100, Sebastian Krzyszkowiak wrote:
> On poniedziałek, 26 stycznia 2026 19:14:55 czas środkowoeuropejski standardowy
> Frank Li wrote:
> > On Sat, Jan 24, 2026 at 02:55:48PM +0100, Sebastian Krzyszkowiak wrote:
> > > According to i.MX 8M Quad Reference Manual, GPU_AHB_CLK_ROOT's maximum
> > > frequency is 400MHz.
> >
> > I checked datasheet
> >
> > Nominal mode—the maximum
> > GPU frequency supported in
> > this mode is 800 MHz.
> >
> > Does difference grade (industry vs consumer) impact max frequency?
>
> No. That sentence relates to GPU_SHADER_CLK_ROOT, which can go up to 1000 MHz,
> but requires "overdrive mode" (higher voltage) when above 800 MHz. It's set to
> 800 MHz in the device tree at the moment.
>
> This patch changes GPU_AHB_CLK_ROOT, which has absolute maximum of 400 MHz
> (see section 5.1.2 Table 5-1).

Yes!

Reviewed-by: Frank Li <Frank.Li@nxp.com>
>
> > Frank
> >
> > > Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
> > > ---
> > >
> > >  arch/arm64/boot/dts/freescale/imx8mq.dtsi | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> > > b/arch/arm64/boot/dts/freescale/imx8mq.dtsi index
> > > 607962f807be..6a25e219832c 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mq.dtsi
> > > @@ -1632,7 +1632,7 @@ gpu: gpu@38000000 {
> > >
> > >  			                         <&clk
> IMX8MQ_GPU_PLL_OUT>,
> > >  			                         <&clk
> IMX8MQ_GPU_PLL>;
> > >
> > >  			assigned-clock-rates = <800000000>,
> <800000000>,
> > >
> > > -			                       <800000000>,
> <800000000>, <0>;
> > > +			                       <800000000>,
> <400000000>, <0>;
> > >
> > >  			power-domains = <&pgc_gpu>;
> > >
> > >  		};
> > >
> > > ---
> > > base-commit: 24d479d26b25bce5faea3ddd9fa8f3a6c3129ea7
> > > change-id: 20260105-imx8mq-gpu-ahb-clock-139ba9ca9a6c
> > >
> > > Best regards,
> > > --
> > > Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
>
>
>
>

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.