* [PATCH v2 2/3] drm/vc4: hdmi: Disable Wifi Frequencies
2020-10-29 13:40 [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence Maxime Ripard
@ 2020-10-29 13:40 ` Maxime Ripard
2020-11-19 9:20 ` Thomas Zimmermann
2020-10-29 13:40 ` [PATCH v2 3/3] ARM: dts: rpi-4: disable wifi frequencies Maxime Ripard
` (2 subsequent siblings)
3 siblings, 1 reply; 10+ messages in thread
From: Maxime Ripard @ 2020-10-29 13:40 UTC (permalink / raw)
To: Mark Rutland, Rob Herring, Frank Rowand, Daniel Vetter,
David Airlie, Maarten Lankhorst, Thomas Zimmermann,
Maxime Ripard, Eric Anholt
Cc: devicetree, Tim Gover, Dave Stevenson, dri-devel,
Nicolas Saenz Julienne, bcm-kernel-feedback-list,
linux-rpi-kernel, Phil Elwell, linux-arm-kernel
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>
---
Changes from v1:
- Change the name of the property
- Test for a range instead of an exact frequency
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 21 +++++++++++++++++++++
drivers/gpu/drm/vc4/vc4_hdmi.h | 8 ++++++++
2 files changed, 29 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 506c12454086..0d72e519aec4 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -760,6 +760,9 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
{
}
+#define WIFI_2_4GHz_CH1_MIN_FREQ 2400000000ULL
+#define WIFI_2_4GHz_CH1_MAX_FREQ 2422000000ULL
+
static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
struct drm_crtc_state *crtc_state,
struct drm_connector_state *conn_state)
@@ -767,12 +770,27 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
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 tmds_rate;
if (vc4_hdmi->variant->unsupported_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 first
+ * WiFi channel (between 2.4GHz and 2.422GHz with 22MHz
+ * bandwidth). Slightly lower the frequency to bring it out of
+ * the WiFi range.
+ */
+ tmds_rate = pixel_rate * 10;
+ if (vc4_hdmi->disable_wifi_frequencies &&
+ (tmds_rate >= WIFI_2_4GHz_CH1_MIN_FREQ &&
+ tmds_rate <= WIFI_2_4GHz_CH1_MAX_FREQ)) {
+ mode->clock = 238560;
+ pixel_rate = mode->clock * 1000;
+ }
+
if (pixel_rate > vc4_hdmi->variant->max_pixel_clock)
return -EINVAL;
@@ -1717,6 +1735,9 @@ 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, "wifi-2.4ghz-coexistence");
+
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 6815e93b1a48..3843be830601 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
@@ -142,6 +142,14 @@ 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
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^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v2 2/3] drm/vc4: hdmi: Disable Wifi Frequencies
2020-10-29 13:40 ` [PATCH v2 2/3] drm/vc4: hdmi: Disable Wifi Frequencies Maxime Ripard
@ 2020-11-19 9:20 ` Thomas Zimmermann
2020-11-19 14:50 ` Maxime Ripard
0 siblings, 1 reply; 10+ messages in thread
From: Thomas Zimmermann @ 2020-11-19 9:20 UTC (permalink / raw)
To: Maxime Ripard, Mark Rutland, Rob Herring, Frank Rowand,
Daniel Vetter, David Airlie, Maarten Lankhorst, Eric Anholt
Cc: linux-arm-kernel, devicetree, Tim Gover, Dave Stevenson,
dri-devel, bcm-kernel-feedback-list, linux-rpi-kernel,
Phil Elwell, Nicolas Saenz Julienne
[-- Attachment #1.1.1.1: Type: text/plain, Size: 3881 bytes --]
Hi
Am 29.10.20 um 14:40 schrieb Maxime Ripard:
> 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>
>
> ---
>
> Changes from v1:
> - Change the name of the property
> - Test for a range instead of an exact frequency
> ---
> drivers/gpu/drm/vc4/vc4_hdmi.c | 21 +++++++++++++++++++++
> drivers/gpu/drm/vc4/vc4_hdmi.h | 8 ++++++++
> 2 files changed, 29 insertions(+)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index 506c12454086..0d72e519aec4 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -760,6 +760,9 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
> {
> }
>
> +#define WIFI_2_4GHz_CH1_MIN_FREQ 2400000000ULL
> +#define WIFI_2_4GHz_CH1_MAX_FREQ 2422000000ULL
> +
> static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
> struct drm_crtc_state *crtc_state,
> struct drm_connector_state *conn_state)
> @@ -767,12 +770,27 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
> 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 tmds_rate;
>
> if (vc4_hdmi->variant->unsupported_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 first
> + * WiFi channel (between 2.4GHz and 2.422GHz with 22MHz
> + * bandwidth). Slightly lower the frequency to bring it out of
> + * the WiFi range.
> + */
> + tmds_rate = pixel_rate * 10;
> + if (vc4_hdmi->disable_wifi_frequencies &&
> + (tmds_rate >= WIFI_2_4GHz_CH1_MIN_FREQ &&
> + tmds_rate <= WIFI_2_4GHz_CH1_MAX_FREQ)) {
> + mode->clock = 238560;
> + pixel_rate = mode->clock * 1000;
> + }
> +
> if (pixel_rate > vc4_hdmi->variant->max_pixel_clock)
> return -EINVAL;
>
> @@ -1717,6 +1735,9 @@ 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, "wifi-2.4ghz-coexistence");
> +
> 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 6815e93b1a48..3843be830601 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
> @@ -142,6 +142,14 @@ 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.
The final sentence sounds like a question. Maybe just write 'Take
evasive actions if...'
Assuming that the display mode still works
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
> + */
> + bool disable_wifi_frequencies;
> +
> struct cec_adapter *cec_adap;
> struct cec_msg cec_rx_msg;
> bool cec_tx_ok;
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
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https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH v2 2/3] drm/vc4: hdmi: Disable Wifi Frequencies
2020-11-19 9:20 ` Thomas Zimmermann
@ 2020-11-19 14:50 ` Maxime Ripard
0 siblings, 0 replies; 10+ messages in thread
From: Maxime Ripard @ 2020-11-19 14:50 UTC (permalink / raw)
To: Thomas Zimmermann
Cc: Mark Rutland, devicetree, Tim Gover, Dave Stevenson,
David Airlie, dri-devel, Rob Herring, bcm-kernel-feedback-list,
linux-rpi-kernel, Daniel Vetter, Frank Rowand, Phil Elwell,
Nicolas Saenz Julienne, linux-arm-kernel
[-- Attachment #1.1: Type: text/plain, Size: 3849 bytes --]
On Thu, Nov 19, 2020 at 10:20:25AM +0100, Thomas Zimmermann wrote:
> Hi
>
> Am 29.10.20 um 14:40 schrieb Maxime Ripard:
> > 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>
> >
> > ---
> >
> > Changes from v1:
> > - Change the name of the property
> > - Test for a range instead of an exact frequency
> > ---
> > drivers/gpu/drm/vc4/vc4_hdmi.c | 21 +++++++++++++++++++++
> > drivers/gpu/drm/vc4/vc4_hdmi.h | 8 ++++++++
> > 2 files changed, 29 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > index 506c12454086..0d72e519aec4 100644
> > --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > @@ -760,6 +760,9 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
> > {
> > }
> > +#define WIFI_2_4GHz_CH1_MIN_FREQ 2400000000ULL
> > +#define WIFI_2_4GHz_CH1_MAX_FREQ 2422000000ULL
> > +
> > static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
> > struct drm_crtc_state *crtc_state,
> > struct drm_connector_state *conn_state)
> > @@ -767,12 +770,27 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
> > 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 tmds_rate;
> > if (vc4_hdmi->variant->unsupported_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 first
> > + * WiFi channel (between 2.4GHz and 2.422GHz with 22MHz
> > + * bandwidth). Slightly lower the frequency to bring it out of
> > + * the WiFi range.
> > + */
> > + tmds_rate = pixel_rate * 10;
> > + if (vc4_hdmi->disable_wifi_frequencies &&
> > + (tmds_rate >= WIFI_2_4GHz_CH1_MIN_FREQ &&
> > + tmds_rate <= WIFI_2_4GHz_CH1_MAX_FREQ)) {
> > + mode->clock = 238560;
> > + pixel_rate = mode->clock * 1000;
> > + }
> > +
> > if (pixel_rate > vc4_hdmi->variant->max_pixel_clock)
> > return -EINVAL;
> > @@ -1717,6 +1735,9 @@ 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, "wifi-2.4ghz-coexistence");
> > +
> > 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 6815e93b1a48..3843be830601 100644
> > --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
> > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
> > @@ -142,6 +142,14 @@ 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.
>
> The final sentence sounds like a question. Maybe just write 'Take evasive
> actions if...'
This was definitely a question, I've added the question mark and applied
the two first patches
> Assuming that the display mode still works
>
> Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Thanks!
Maxime
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^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v2 3/3] ARM: dts: rpi-4: disable wifi frequencies
2020-10-29 13:40 [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence Maxime Ripard
2020-10-29 13:40 ` [PATCH v2 2/3] drm/vc4: hdmi: Disable Wifi Frequencies Maxime Ripard
@ 2020-10-29 13:40 ` Maxime Ripard
2020-11-20 16:45 ` Nicolas Saenz Julienne
2020-10-29 17:43 ` [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence Nicolas Saenz Julienne
2020-11-04 21:40 ` Rob Herring
3 siblings, 1 reply; 10+ messages in thread
From: Maxime Ripard @ 2020-10-29 13:40 UTC (permalink / raw)
To: Mark Rutland, Rob Herring, Frank Rowand, Daniel Vetter,
David Airlie, Maarten Lankhorst, Thomas Zimmermann,
Maxime Ripard, Eric Anholt
Cc: devicetree, Tim Gover, Dave Stevenson, dri-devel,
Nicolas Saenz Julienne, bcm-kernel-feedback-list,
linux-rpi-kernel, Phil Elwell, linux-arm-kernel
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>
---
Changes from v1:
- Changed the property name
---
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 09a1182c2936..403bacf986eb 100644
--- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
+++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
@@ -181,12 +181,14 @@ &gpio {
&hdmi0 {
clocks = <&firmware_clocks 13>, <&firmware_clocks 14>, <&dvp 0>, <&clk_27MHz>;
clock-names = "hdmi", "bvb", "audio", "cec";
+ wifi-2.4ghz-coexistence;
status = "okay";
};
&hdmi1 {
clocks = <&firmware_clocks 13>, <&firmware_clocks 14>, <&dvp 1>, <&clk_27MHz>;
clock-names = "hdmi", "bvb", "audio", "cec";
+ wifi-2.4ghz-coexistence;
status = "okay";
};
--
2.26.2
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^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v2 3/3] ARM: dts: rpi-4: disable wifi frequencies
2020-10-29 13:40 ` [PATCH v2 3/3] ARM: dts: rpi-4: disable wifi frequencies Maxime Ripard
@ 2020-11-20 16:45 ` Nicolas Saenz Julienne
0 siblings, 0 replies; 10+ messages in thread
From: Nicolas Saenz Julienne @ 2020-11-20 16:45 UTC (permalink / raw)
To: Maxime Ripard, Mark Rutland, Rob Herring, Frank Rowand,
Daniel Vetter, David Airlie, Maarten Lankhorst,
Thomas Zimmermann, Eric Anholt
Cc: devicetree, Tim Gover, Dave Stevenson, dri-devel,
bcm-kernel-feedback-list, linux-rpi-kernel, Phil Elwell,
linux-arm-kernel
[-- Attachment #1.1: Type: text/plain, Size: 375 bytes --]
On Thu, 2020-10-29 at 14:40 +0100, Maxime Ripard wrote:
> 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>
>
> ---
>
> Changes from v1:
> - Changed the property name
Applied for next. Thanks!
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence
2020-10-29 13:40 [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence Maxime Ripard
2020-10-29 13:40 ` [PATCH v2 2/3] drm/vc4: hdmi: Disable Wifi Frequencies Maxime Ripard
2020-10-29 13:40 ` [PATCH v2 3/3] ARM: dts: rpi-4: disable wifi frequencies Maxime Ripard
@ 2020-10-29 17:43 ` Nicolas Saenz Julienne
2020-10-29 18:07 ` Maxime Ripard
2020-11-04 21:40 ` Rob Herring
3 siblings, 1 reply; 10+ messages in thread
From: Nicolas Saenz Julienne @ 2020-10-29 17:43 UTC (permalink / raw)
To: Maxime Ripard, Mark Rutland, Rob Herring, Frank Rowand,
Daniel Vetter, David Airlie, Maarten Lankhorst,
Thomas Zimmermann, Eric Anholt
Cc: devicetree, Tim Gover, Dave Stevenson, dri-devel,
bcm-kernel-feedback-list, linux-rpi-kernel, Phil Elwell,
linux-arm-kernel
[-- Attachment #1.1: Type: text/plain, Size: 1627 bytes --]
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
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence
2020-10-29 17:43 ` [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence Nicolas Saenz Julienne
@ 2020-10-29 18:07 ` Maxime Ripard
2020-10-29 18:16 ` Nicolas Saenz Julienne
0 siblings, 1 reply; 10+ messages in thread
From: Maxime Ripard @ 2020-10-29 18:07 UTC (permalink / raw)
To: Nicolas Saenz Julienne
Cc: Mark Rutland, devicetree, Tim Gover, Dave Stevenson,
David Airlie, dri-devel, Rob Herring, bcm-kernel-feedback-list,
linux-rpi-kernel, Thomas Zimmermann, Daniel Vetter, Frank Rowand,
Phil Elwell, linux-arm-kernel
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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
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence
2020-10-29 18:07 ` Maxime Ripard
@ 2020-10-29 18:16 ` Nicolas Saenz Julienne
0 siblings, 0 replies; 10+ messages in thread
From: Nicolas Saenz Julienne @ 2020-10-29 18:16 UTC (permalink / raw)
To: Maxime Ripard
Cc: Mark Rutland, devicetree, Tim Gover, Dave Stevenson,
David Airlie, dri-devel, Rob Herring, bcm-kernel-feedback-list,
linux-rpi-kernel, Thomas Zimmermann, Daniel Vetter, Frank Rowand,
Phil Elwell, linux-arm-kernel
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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
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence
2020-10-29 13:40 [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence Maxime Ripard
` (2 preceding siblings ...)
2020-10-29 17:43 ` [PATCH v2 1/3] dt-bindings: display: Add a property to deal with WiFi coexistence Nicolas Saenz Julienne
@ 2020-11-04 21:40 ` Rob Herring
3 siblings, 0 replies; 10+ messages in thread
From: Rob Herring @ 2020-11-04 21:40 UTC (permalink / raw)
To: Maxime Ripard
Cc: Mark Rutland, devicetree, Tim Gover, Dave Stevenson,
David Airlie, dri-devel, Rob Herring, bcm-kernel-feedback-list,
Nicolas Saenz Julienne, Thomas Zimmermann, Daniel Vetter,
Frank Rowand, Phil Elwell, linux-arm-kernel, linux-rpi-kernel
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>
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^ permalink raw reply [flat|nested] 10+ messages in thread