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@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? + 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; + + pixel_rate = mode->clock * 1000; if (mode->flags & DRM_MODE_FLAG_DBLCLK) pixel_rate *= 2;
@@ -1837,6 +1846,9 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data) vc4_hdmi->hpd_active_low = hpd_gpio_flags & OF_GPIO_ACTIVE_LOW; }
+ vc4_hdmi->disable_wifi_frequencies = + of_property_read_bool(dev->of_node, "raspberrypi,disable-wifi-frequencies"); + pm_runtime_enable(dev);
drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS); diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h index 40e51ece8efe..6618ee758890 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.h +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h @@ -143,6 +143,14 @@ struct vc4_hdmi { int hpd_gpio; bool hpd_active_low;
+ /* + * On some systems (like the RPi4), some modes are in the same + * frequency range than the WiFi channels (1440p@60Hz for + * example). Should we take evasive actions because that system + * has a wifi adapter. + */ + bool disable_wifi_frequencies; + struct cec_adapter *cec_adap; struct cec_msg cec_rx_msg; bool cec_tx_ok;
The RPi4 WiFi chip and HDMI outputs have some frequency overlap with crosstalk around 2.4GHz. Let's mark it as such so we can use some evasive maneuvers.
Signed-off-by: Maxime Ripard maxime@cerno.tech --- arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts index ca24c2c737ab..1b739c3a9a12 100644 --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts @@ -174,12 +174,14 @@ &gpio { &hdmi0 { clocks = <&firmware_clocks 13>, <&firmware_clocks 14>, <&dvp 0>, <&clk_27MHz>; clock-names = "hdmi", "bvb", "audio", "cec"; + raspberrypi,disable-wifi-frequencies; status = "okay"; };
&hdmi1 { clocks = <&firmware_clocks 13>, <&firmware_clocks 14>, <&dvp 1>, <&clk_27MHz>; clock-names = "hdmi", "bvb", "audio", "cec"; + raspberrypi,disable-wifi-frequencies; status = "okay"; };
On Mon, Sep 28, 2020 at 9:06 AM Maxime Ripard maxime@cerno.tech 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@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 beavoided?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. -Daniel
pixel_rate = mode->clock * 1000; if (mode->flags & DRM_MODE_FLAG_DBLCLK) pixel_rate *= 2;@@ -1837,6 +1846,9 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data) vc4_hdmi->hpd_active_low = hpd_gpio_flags & OF_GPIO_ACTIVE_LOW; }
vc4_hdmi->disable_wifi_frequencies =of_property_read_bool(dev->of_node, "raspberrypi,disable-wifi-frequencies");pm_runtime_enable(dev); drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h index 40e51ece8efe..6618ee758890 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.h +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h @@ -143,6 +143,14 @@ struct vc4_hdmi { int hpd_gpio; bool hpd_active_low;
/** On some systems (like the RPi4), some modes are in the same* frequency range than the WiFi channels (1440p@60Hz for* example). Should we take evasive actions because that system* has a wifi adapter.*/bool disable_wifi_frequencies;struct cec_adapter *cec_adap; struct cec_msg cec_rx_msg; bool cec_tx_ok;-- 2.26.2
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
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@cerno.tech 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@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 beavoided?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
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@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 beavoided?
Based on googling the issue, perhaps should be a common property?
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@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 beavoided?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
dri-devel@lists.freedesktop.org
-
Daniel Vetter -
Maxime Ripard -
Rob Herring