diff mbox series

[v2,1/3] dt-bindings: display: Add a property to deal with WiFi coexistence

Message ID 20201029134018.1948636-1-maxime@cerno.tech
State New, archived
Headers show
Series [v2,1/3] dt-bindings: display: Add a property to deal with WiFi coexistence | expand

Commit Message

Maxime Ripard Oct. 29, 2020, 1:40 p.m. UTC
The RaspberryPi4 has both a WiFi chip and HDMI outputs capable of doing
4k. Unfortunately, the 1440p resolution at 60Hz has a TMDS rate on the
HDMI cable right in the middle of the first Wifi channel.

Add a property to our HDMI controller, that could be reused by other
similar HDMI controllers, to allow the OS to take whatever measure is
necessary to avoid that crosstalk.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

---

Changes from v1:
  - Renamed the property
  - Split it into a separate patch
---
 .../devicetree/bindings/display/brcm,bcm2711-hdmi.yaml      | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Nicolas Saenz Julienne Oct. 29, 2020, 5:43 p.m. UTC | #1
Hi maxime,

On Thu, 2020-10-29 at 14:40 +0100, Maxime Ripard wrote:
> The RaspberryPi4 has both a WiFi chip and HDMI outputs capable of doing
> 4k. Unfortunately, the 1440p resolution at 60Hz has a TMDS rate on the
> HDMI cable right in the middle of the first Wifi channel.
> 
> Add a property to our HDMI controller, that could be reused by other
> similar HDMI controllers, to allow the OS to take whatever measure is
> necessary to avoid that crosstalk.
> 
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> 
> ---
> 
> Changes from v1:
>   - Renamed the property
>   - Split it into a separate patch
> ---
>  .../devicetree/bindings/display/brcm,bcm2711-hdmi.yaml      | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> index 03a76729d26c..7ce06f9f9f8e 100644
> --- a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> +++ b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> @@ -76,6 +76,12 @@ properties:
>    resets:
>      maxItems: 1
>  
> +  wifi-2.4ghz-coexistence:

I see you already renamed the property, but I can't seem to find v1 of the
series online. Sorry if this is redundant:

I wonder if it'd make sense to prefix the property like this:
"raspberrypi,wifi-2.4ghz-coexistence." I tend to associate the lack of prefix
with generic properties, and also thought it was a rule. Although I may have as
well imagined it.

Other than that the series looks OK to me.

Regards,
Nicolas
Maxime Ripard Oct. 29, 2020, 6:07 p.m. UTC | #2
Hi Nicolas,

On Thu, Oct 29, 2020 at 06:43:27PM +0100, Nicolas Saenz Julienne wrote:
> Hi maxime,
> 
> On Thu, 2020-10-29 at 14:40 +0100, Maxime Ripard wrote:
> > The RaspberryPi4 has both a WiFi chip and HDMI outputs capable of doing
> > 4k. Unfortunately, the 1440p resolution at 60Hz has a TMDS rate on the
> > HDMI cable right in the middle of the first Wifi channel.
> > 
> > Add a property to our HDMI controller, that could be reused by other
> > similar HDMI controllers, to allow the OS to take whatever measure is
> > necessary to avoid that crosstalk.
> > 
> > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> > 
> > ---
> > 
> > Changes from v1:
> >   - Renamed the property
> >   - Split it into a separate patch
> > ---
> >  .../devicetree/bindings/display/brcm,bcm2711-hdmi.yaml      | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> > index 03a76729d26c..7ce06f9f9f8e 100644
> > --- a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> > +++ b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> > @@ -76,6 +76,12 @@ properties:
> >    resets:
> >      maxItems: 1
> >  
> > +  wifi-2.4ghz-coexistence:
> 
> I see you already renamed the property, but I can't seem to find v1 of the
> series online.

I realized I didn't put you in Cc for the first version, sorry, you'll find it here:
https://lore.kernel.org/dri-devel/20200925130744.575725-1-maxime@cerno.tech/

> Sorry if this is redundant:
> 
> I wonder if it'd make sense to prefix the property like this:
> "raspberrypi,wifi-2.4ghz-coexistence." I tend to associate the lack of prefix
> with generic properties, and also thought it was a rule. Although I may have as
> well imagined it.

Rob in the first iteration asked for the opposite :)

It used to be a vendor-specific property, and since this issue is
basically cross-platform (as long as you can support 1440p and have
WiFi), it makes sense to make this a generic property

Maxime
Nicolas Saenz Julienne Oct. 29, 2020, 6:16 p.m. UTC | #3
On Thu, 2020-10-29 at 19:07 +0100, Maxime Ripard wrote:
> Hi Nicolas,
> 
> On Thu, Oct 29, 2020 at 06:43:27PM +0100, Nicolas Saenz Julienne wrote:
> > Hi maxime,
> > 
> > On Thu, 2020-10-29 at 14:40 +0100, Maxime Ripard wrote:
> > > The RaspberryPi4 has both a WiFi chip and HDMI outputs capable of doing
> > > 4k. Unfortunately, the 1440p resolution at 60Hz has a TMDS rate on the
> > > HDMI cable right in the middle of the first Wifi channel.
> > > 
> > > Add a property to our HDMI controller, that could be reused by other
> > > similar HDMI controllers, to allow the OS to take whatever measure is
> > > necessary to avoid that crosstalk.
> > > 
> > > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> > > 
> > > ---
> > > 
> > > Changes from v1:
> > >   - Renamed the property
> > >   - Split it into a separate patch
> > > ---
> > >  .../devicetree/bindings/display/brcm,bcm2711-hdmi.yaml      | 6 ++++++
> > >  1 file changed, 6 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> > > index 03a76729d26c..7ce06f9f9f8e 100644
> > > --- a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> > > +++ b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> > > @@ -76,6 +76,12 @@ properties:
> > >    resets:
> > >      maxItems: 1
> > >  
> > > +  wifi-2.4ghz-coexistence:
> > 
> > I see you already renamed the property, but I can't seem to find v1 of the
> > series online.
> 
> I realized I didn't put you in Cc for the first version, sorry, you'll find it here:
> https://lore.kernel.org/dri-devel/20200925130744.575725-1-maxime@cerno.tech/
> 
> > Sorry if this is redundant:
> > 
> > I wonder if it'd make sense to prefix the property like this:
> > "raspberrypi,wifi-2.4ghz-coexistence." I tend to associate the lack of prefix
> > with generic properties, and also thought it was a rule. Although I may have as
> > well imagined it.
> 
> Rob in the first iteration asked for the opposite :)

Fair enough, then:

Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

Regards,
Nicolas
Rob Herring Nov. 4, 2020, 9:40 p.m. UTC | #4
On Thu, 29 Oct 2020 14:40:16 +0100, Maxime Ripard wrote:
> The RaspberryPi4 has both a WiFi chip and HDMI outputs capable of doing
> 4k. Unfortunately, the 1440p resolution at 60Hz has a TMDS rate on the
> HDMI cable right in the middle of the first Wifi channel.
> 
> Add a property to our HDMI controller, that could be reused by other
> similar HDMI controllers, to allow the OS to take whatever measure is
> necessary to avoid that crosstalk.
> 
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> 
> ---
> 
> Changes from v1:
>   - Renamed the property
>   - Split it into a separate patch
> ---
>  .../devicetree/bindings/display/brcm,bcm2711-hdmi.yaml      | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
index 03a76729d26c..7ce06f9f9f8e 100644
--- a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
+++ b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
@@ -76,6 +76,12 @@  properties:
   resets:
     maxItems: 1
 
+  wifi-2.4ghz-coexistence:
+    type: boolean
+    description: >
+      Should the pixel frequencies in the WiFi frequencies range be
+      avoided?
+
 required:
   - compatible
   - reg