Hi Daniel, On Mon, Sep 28, 2020 at 11:02:11AM +0200, Daniel Vetter wrote: > On Mon, Sep 28, 2020 at 9:06 AM Maxime Ripard <maxime@xxxxxxxxxx> 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@xxxxxxxxxx> > > --- > > .../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? > > + > > required: > > - compatible > > - reg > > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c > > index acfb4e235214..74da7c00ecd0 100644 > > --- a/drivers/gpu/drm/vc4/vc4_hdmi.c > > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c > > @@ -877,13 +877,22 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder, > > struct vc4_hdmi_connector_state *vc4_state = conn_state_to_vc4_hdmi_conn_state(conn_state); > > struct drm_display_mode *mode = &crtc_state->adjusted_mode; > > struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder); > > - unsigned long long pixel_rate = mode->clock * 1000; > > + unsigned long long pixel_rate; > > > > if (vc4_hdmi->variant->broken_odd_h_timings && > > ((mode->hdisplay % 2) || (mode->hsync_start % 2) || > > (mode->hsync_end % 2) || (mode->htotal % 2))) > > return -EINVAL; > > > > + /* > > + * The 1440p@60 pixel rate is in the same range than the WiFi > > + * channels. Slightly lower the frequency to bring it out of the > > + * WiFi range. > > + */ > > + if (vc4_hdmi->disable_wifi_frequencies && mode->clock == 241500) > > + mode->clock = 238560; > > Don't you want to map for a (narrow) range of frequencies here? Just > for that infamous 60p vs 59.99p thing and similar. And I think that > would still be in that band you want to avoid. Testing for a range seems better indeed, I'll send a new version Thanks! Maxime
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