[PATCH 1/2] drm/vc4: hdmi: Disable Wifi Frequencies

Maxime Ripard maxime at cerno.tech
Wed Sep 30 13:04:59 UTC 2020


Hi Rob,

On Tue, Sep 29, 2020 at 02:00:55PM -0500, Rob Herring wrote:
> On Fri, Sep 25, 2020 at 03:07:43PM +0200, Maxime Ripard wrote:
> > There's cross-talk on the RPi4 between the 2.4GHz channels used by the WiFi
> > chip and some resolutions, most notably 1440p at 60Hz.
> > 
> > In such a case, we can either reject entirely the mode, or lower slightly
> > the pixel frequency to remove the overlap. Let's go for the latter.
> > 
> > Signed-off-by: Maxime Ripard <maxime at cerno.tech>
> > ---
> >  .../bindings/display/brcm,bcm2711-hdmi.yaml        |  6 ++++++
> >  drivers/gpu/drm/vc4/vc4_hdmi.c                     | 14 +++++++++++++-
> >  drivers/gpu/drm/vc4/vc4_hdmi.h                     |  8 ++++++++
> >  3 files changed, 27 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml b/Documentation/devicetree/bindings/display/brcm,bcm2711-hdmi.yaml
> > index 03a76729d26c..63e7fe999c0a 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
> >  
> > +  raspberrypi,disable-wifi-frequencies:
> > +    type: boolean
> > +    description: >
> > +      Should the pixel frequencies in the WiFi frequencies range be
> > +      avoided?
> 
> Based on googling the issue, perhaps should be a common property?

This is a fairly generic issue indeed, but went for the most
non-intrusive way. Do you have a better idea of a generic name, or do
you just want me to drop the vendor prefix?

Maxime
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