[PATCH v3 0/3] drm/vc4: Use the firmware to stop the display pipeline

[PATCH v3 0/3] drm/vc4: Use the firmware to stop the display pipeline

[Maxime Ripard]

Hi,

The VC4 driver has had limited support to disable the HDMI controllers and
pixelvalves at boot if the firmware has enabled them.

However, this proved to be limited, and a bit unreliable so a new firmware
command has been introduced some time ago to make it free all its resources and
disable any display output it might have enabled.

This series takes advantage of that command to call it once the transition from
simplefb to the KMS driver has been done.

Let me know what you think,
Maxime

---

Changes from v2:
  - Switch back to rpi_firmware_get / rpi_firmware_put
  - Moved the rpi_firmware pointer to a local variable

Changes from v1:
  - Use of_find_compatible_node instead of a phandle
  - Use devm_rpi_firmware_get

Maxime Ripard (3):
  firmware: raspberrypi: Add RPI_FIRMWARE_NOTIFY_DISPLAY_DONE
  drm/vc4: Remove conflicting framebuffers before callind bind_all
  drm/vc4: Notify the firmware when DRM is in charge

 drivers/gpu/drm/vc4/vc4_drv.c              | 30 +++++++++++++++++++---
 include/soc/bcm2835/raspberrypi-firmware.h |  1 +
 2 files changed, 27 insertions(+), 4 deletions(-)

-- 
2.33.1

[PATCH v3 0/3] drm/vc4: Use the firmware to stop the display pipeline

[Maxime Ripard]

Hi,

The VC4 driver has had limited support to disable the HDMI controllers and
pixelvalves at boot if the firmware has enabled them.

However, this proved to be limited, and a bit unreliable so a new firmware
command has been introduced some time ago to make it free all its resources and
disable any display output it might have enabled.

This series takes advantage of that command to call it once the transition from
simplefb to the KMS driver has been done.

Let me know what you think,
Maxime

---

Changes from v2:
  - Switch back to rpi_firmware_get / rpi_firmware_put
  - Moved the rpi_firmware pointer to a local variable

Changes from v1:
  - Use of_find_compatible_node instead of a phandle
  - Use devm_rpi_firmware_get

Maxime Ripard (3):
  firmware: raspberrypi: Add RPI_FIRMWARE_NOTIFY_DISPLAY_DONE
  drm/vc4: Remove conflicting framebuffers before callind bind_all
  drm/vc4: Notify the firmware when DRM is in charge

 drivers/gpu/drm/vc4/vc4_drv.c              | 30 +++++++++++++++++++---
 include/soc/bcm2835/raspberrypi-firmware.h |  1 +
 2 files changed, 27 insertions(+), 4 deletions(-)

-- 
2.33.1

[PATCH v3 0/3] drm/vc4: Use the firmware to stop the display pipeline

[Maxime Ripard]

Hi,

The VC4 driver has had limited support to disable the HDMI controllers and
pixelvalves at boot if the firmware has enabled them.

However, this proved to be limited, and a bit unreliable so a new firmware
command has been introduced some time ago to make it free all its resources and
disable any display output it might have enabled.

This series takes advantage of that command to call it once the transition from
simplefb to the KMS driver has been done.

Let me know what you think,
Maxime

---

Changes from v2:
  - Switch back to rpi_firmware_get / rpi_firmware_put
  - Moved the rpi_firmware pointer to a local variable

Changes from v1:
  - Use of_find_compatible_node instead of a phandle
  - Use devm_rpi_firmware_get

Maxime Ripard (3):
  firmware: raspberrypi: Add RPI_FIRMWARE_NOTIFY_DISPLAY_DONE
  drm/vc4: Remove conflicting framebuffers before callind bind_all
  drm/vc4: Notify the firmware when DRM is in charge

 drivers/gpu/drm/vc4/vc4_drv.c              | 30 +++++++++++++++++++---
 include/soc/bcm2835/raspberrypi-firmware.h |  1 +
 2 files changed, 27 insertions(+), 4 deletions(-)

-- 
2.33.1


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[PATCH v3 1/3] firmware: raspberrypi: Add RPI_FIRMWARE_NOTIFY_DISPLAY_DONE

[Maxime Ripard]

The RPI_FIRMWARE_NOTIFY_DISPLAY_DONE firmware call allows to tell the
firmware the kernel is in charge of the display now and the firmware can
free whatever resources it was using.

Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 include/soc/bcm2835/raspberrypi-firmware.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index 73ad784fca96..811ea668c4a1 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -91,6 +91,7 @@ enum rpi_firmware_property_tag {
 	RPI_FIRMWARE_GET_POE_HAT_VAL =                        0x00030049,
 	RPI_FIRMWARE_SET_POE_HAT_VAL =                        0x00030050,
 	RPI_FIRMWARE_NOTIFY_XHCI_RESET =                      0x00030058,
+	RPI_FIRMWARE_NOTIFY_DISPLAY_DONE =                    0x00030066,
 
 	/* Dispmanx TAGS */
 	RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE =                   0x00040001,
-- 
2.33.1

[PATCH v3 1/3] firmware: raspberrypi: Add RPI_FIRMWARE_NOTIFY_DISPLAY_DONE

[Maxime Ripard]

The RPI_FIRMWARE_NOTIFY_DISPLAY_DONE firmware call allows to tell the
firmware the kernel is in charge of the display now and the firmware can
free whatever resources it was using.

Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 include/soc/bcm2835/raspberrypi-firmware.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index 73ad784fca96..811ea668c4a1 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -91,6 +91,7 @@ enum rpi_firmware_property_tag {
 	RPI_FIRMWARE_GET_POE_HAT_VAL =                        0x00030049,
 	RPI_FIRMWARE_SET_POE_HAT_VAL =                        0x00030050,
 	RPI_FIRMWARE_NOTIFY_XHCI_RESET =                      0x00030058,
+	RPI_FIRMWARE_NOTIFY_DISPLAY_DONE =                    0x00030066,
 
 	/* Dispmanx TAGS */
 	RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE =                   0x00040001,
-- 
2.33.1

[PATCH v3 1/3] firmware: raspberrypi: Add RPI_FIRMWARE_NOTIFY_DISPLAY_DONE

[Maxime Ripard]

The RPI_FIRMWARE_NOTIFY_DISPLAY_DONE firmware call allows to tell the
firmware the kernel is in charge of the display now and the firmware can
free whatever resources it was using.

Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 include/soc/bcm2835/raspberrypi-firmware.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index 73ad784fca96..811ea668c4a1 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -91,6 +91,7 @@ enum rpi_firmware_property_tag {
 	RPI_FIRMWARE_GET_POE_HAT_VAL =                        0x00030049,
 	RPI_FIRMWARE_SET_POE_HAT_VAL =                        0x00030050,
 	RPI_FIRMWARE_NOTIFY_XHCI_RESET =                      0x00030058,
+	RPI_FIRMWARE_NOTIFY_DISPLAY_DONE =                    0x00030066,
 
 	/* Dispmanx TAGS */
 	RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE =                   0x00040001,
-- 
2.33.1


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[PATCH v3 2/3] drm/vc4: Remove conflicting framebuffers before callind bind_all

[Maxime Ripard]

The bind hooks will modify their controller registers, so simplefb is
going to be unusable anyway. Let's avoid any transient state where it
could still be in the system but no longer functionnal.

Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 16abc3a3d601..8ab89f805826 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -251,6 +251,10 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		return ret;
 
+	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
+	if (ret)
+		return ret;
+
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
@@ -259,10 +263,6 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		goto unbind_all;
 
-	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
-	if (ret)
-		goto unbind_all;
-
 	ret = vc4_kms_load(drm);
 	if (ret < 0)
 		goto unbind_all;
-- 
2.33.1

[PATCH v3 2/3] drm/vc4: Remove conflicting framebuffers before callind bind_all

[Maxime Ripard]

The bind hooks will modify their controller registers, so simplefb is
going to be unusable anyway. Let's avoid any transient state where it
could still be in the system but no longer functionnal.

Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 16abc3a3d601..8ab89f805826 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -251,6 +251,10 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		return ret;
 
+	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
+	if (ret)
+		return ret;
+
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
@@ -259,10 +263,6 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		goto unbind_all;
 
-	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
-	if (ret)
-		goto unbind_all;
-
 	ret = vc4_kms_load(drm);
 	if (ret < 0)
 		goto unbind_all;
-- 
2.33.1

[PATCH v3 2/3] drm/vc4: Remove conflicting framebuffers before callind bind_all

[Maxime Ripard]

The bind hooks will modify their controller registers, so simplefb is
going to be unusable anyway. Let's avoid any transient state where it
could still be in the system but no longer functionnal.

Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 16abc3a3d601..8ab89f805826 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -251,6 +251,10 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		return ret;
 
+	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
+	if (ret)
+		return ret;
+
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
@@ -259,10 +263,6 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		goto unbind_all;
 
-	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
-	if (ret)
-		goto unbind_all;
-
 	ret = vc4_kms_load(drm);
 	if (ret < 0)
 		goto unbind_all;
-- 
2.33.1


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[PATCH v3 3/3] drm/vc4: Notify the firmware when DRM is in charge

[Maxime Ripard]

Once the call to drm_fb_helper_remove_conflicting_framebuffers() has
been made, simplefb has been unregistered and the KMS driver is entirely
in charge of the display.

Thus, we can notify the firmware it can free whatever resource it was
using to maintain simplefb functional.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 8ab89f805826..e26897cb49a9 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -37,6 +37,8 @@
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_vblank.h>
 
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
 #include "uapi/drm/vc4_drm.h"
 
 #include "vc4_drv.h"
@@ -215,6 +217,7 @@ static void vc4_match_add_drivers(struct device *dev,
 static int vc4_drm_bind(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
+	struct rpi_firmware *firmware = NULL;
 	struct drm_device *drm;
 	struct vc4_dev *vc4;
 	struct device_node *node;
@@ -251,10 +254,29 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		return ret;
 
+	node = of_find_compatible_node(NULL, NULL, "raspberrypi,bcm2835-firmware");
+	if (node) {
+		firmware = rpi_firmware_get(node);
+		of_node_put(node);
+
+		if (!firmware)
+			return -EPROBE_DEFER;
+	}
+
 	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
 	if (ret)
 		return ret;
 
+	if (firmware) {
+		ret = rpi_firmware_property(firmware,
+					    RPI_FIRMWARE_NOTIFY_DISPLAY_DONE,
+					    NULL, 0);
+		if (ret)
+			drm_warn(drm, "Couldn't stop firmware display driver: %d\n", ret);
+
+		rpi_firmware_put(firmware);
+	}
+
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
-- 
2.33.1

[PATCH v3 3/3] drm/vc4: Notify the firmware when DRM is in charge

[Maxime Ripard]

Once the call to drm_fb_helper_remove_conflicting_framebuffers() has
been made, simplefb has been unregistered and the KMS driver is entirely
in charge of the display.

Thus, we can notify the firmware it can free whatever resource it was
using to maintain simplefb functional.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 8ab89f805826..e26897cb49a9 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -37,6 +37,8 @@
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_vblank.h>
 
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
 #include "uapi/drm/vc4_drm.h"
 
 #include "vc4_drv.h"
@@ -215,6 +217,7 @@ static void vc4_match_add_drivers(struct device *dev,
 static int vc4_drm_bind(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
+	struct rpi_firmware *firmware = NULL;
 	struct drm_device *drm;
 	struct vc4_dev *vc4;
 	struct device_node *node;
@@ -251,10 +254,29 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		return ret;
 
+	node = of_find_compatible_node(NULL, NULL, "raspberrypi,bcm2835-firmware");
+	if (node) {
+		firmware = rpi_firmware_get(node);
+		of_node_put(node);
+
+		if (!firmware)
+			return -EPROBE_DEFER;
+	}
+
 	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
 	if (ret)
 		return ret;
 
+	if (firmware) {
+		ret = rpi_firmware_property(firmware,
+					    RPI_FIRMWARE_NOTIFY_DISPLAY_DONE,
+					    NULL, 0);
+		if (ret)
+			drm_warn(drm, "Couldn't stop firmware display driver: %d\n", ret);
+
+		rpi_firmware_put(firmware);
+	}
+
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
-- 
2.33.1

[PATCH v3 3/3] drm/vc4: Notify the firmware when DRM is in charge

[Maxime Ripard]

Once the call to drm_fb_helper_remove_conflicting_framebuffers() has
been made, simplefb has been unregistered and the KMS driver is entirely
in charge of the display.

Thus, we can notify the firmware it can free whatever resource it was
using to maintain simplefb functional.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_drv.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index 8ab89f805826..e26897cb49a9 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -37,6 +37,8 @@
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_vblank.h>
 
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
 #include "uapi/drm/vc4_drm.h"
 
 #include "vc4_drv.h"
@@ -215,6 +217,7 @@ static void vc4_match_add_drivers(struct device *dev,
 static int vc4_drm_bind(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
+	struct rpi_firmware *firmware = NULL;
 	struct drm_device *drm;
 	struct vc4_dev *vc4;
 	struct device_node *node;
@@ -251,10 +254,29 @@ static int vc4_drm_bind(struct device *dev)
 	if (ret)
 		return ret;
 
+	node = of_find_compatible_node(NULL, NULL, "raspberrypi,bcm2835-firmware");
+	if (node) {
+		firmware = rpi_firmware_get(node);
+		of_node_put(node);
+
+		if (!firmware)
+			return -EPROBE_DEFER;
+	}
+
 	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
 	if (ret)
 		return ret;
 
+	if (firmware) {
+		ret = rpi_firmware_property(firmware,
+					    RPI_FIRMWARE_NOTIFY_DISPLAY_DONE,
+					    NULL, 0);
+		if (ret)
+			drm_warn(drm, "Couldn't stop firmware display driver: %d\n", ret);
+
+		rpi_firmware_put(firmware);
+	}
+
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
-- 
2.33.1


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Re: [PATCH v3 2/3] drm/vc4: Remove conflicting framebuffers before callind bind_all

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 2023 bytes --]

Hi Maxime

Am 13.12.21 um 10:25 schrieb Maxime Ripard:
> The bind hooks will modify their controller registers, so simplefb is
> going to be unusable anyway. Let's avoid any transient state where it
> could still be in the system but no longer functionnal.
> 
> Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---
>   drivers/gpu/drm/vc4/vc4_drv.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
> index 16abc3a3d601..8ab89f805826 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.c
> +++ b/drivers/gpu/drm/vc4/vc4_drv.c
> @@ -251,6 +251,10 @@ static int vc4_drm_bind(struct device *dev)

Since you work on this, I'd like to suggest to call 
drm_firmware_drivers_only() at the very top of this function. It's our 
new interface for the kernel's nomodeset argument. If it returns false, 
the user has disabled native drivers for this boot. The generic DRM 
driver will continue to run the device.

>   	if (ret)
>   		return ret;
>   
> +	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
> +	if (ret)
> +		return ret;
> +

There's quite a bit of work being done before calling this function. 
None of it is allowed to touch HW.

Is that reliable? If so, the code is fine, otherwise the call should go 
to the top of the function.

Best regards
Thomas

>   	ret = component_bind_all(dev, drm);
>   	if (ret)
>   		return ret;
> @@ -259,10 +263,6 @@ static int vc4_drm_bind(struct device *dev)
>   	if (ret)
>   		goto unbind_all;
>   
> -	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
> -	if (ret)
> -		goto unbind_all;
> -
>   	ret = vc4_kms_load(drm);
>   	if (ret < 0)
>   		goto unbind_all;
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

[-- Attachment #2: OpenPGP digital signature --]
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Re: [PATCH v3 2/3] drm/vc4: Remove conflicting framebuffers before callind bind_all

[Thomas Zimmermann]

[-- Attachment #1.1.1: Type: text/plain, Size: 2023 bytes --]

Hi Maxime

Am 13.12.21 um 10:25 schrieb Maxime Ripard:
> The bind hooks will modify their controller registers, so simplefb is
> going to be unusable anyway. Let's avoid any transient state where it
> could still be in the system but no longer functionnal.
> 
> Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---
>   drivers/gpu/drm/vc4/vc4_drv.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
> index 16abc3a3d601..8ab89f805826 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.c
> +++ b/drivers/gpu/drm/vc4/vc4_drv.c
> @@ -251,6 +251,10 @@ static int vc4_drm_bind(struct device *dev)

Since you work on this, I'd like to suggest to call 
drm_firmware_drivers_only() at the very top of this function. It's our 
new interface for the kernel's nomodeset argument. If it returns false, 
the user has disabled native drivers for this boot. The generic DRM 
driver will continue to run the device.

>   	if (ret)
>   		return ret;
>   
> +	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
> +	if (ret)
> +		return ret;
> +

There's quite a bit of work being done before calling this function. 
None of it is allowed to touch HW.

Is that reliable? If so, the code is fine, otherwise the call should go 
to the top of the function.

Best regards
Thomas

>   	ret = component_bind_all(dev, drm);
>   	if (ret)
>   		return ret;
> @@ -259,10 +263,6 @@ static int vc4_drm_bind(struct device *dev)
>   	if (ret)
>   		goto unbind_all;
>   
> -	ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
> -	if (ret)
> -		goto unbind_all;
> -
>   	ret = vc4_kms_load(drm);
>   	if (ret < 0)
>   		goto unbind_all;
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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Re: [PATCH v3 2/3] drm/vc4: Remove conflicting framebuffers before callind bind_all

[Thomas Zimmermann]

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Am 13.12.21 um 10:47 schrieb Thomas Zimmermann:
> Hi Maxime
> 
> Am 13.12.21 um 10:25 schrieb Maxime Ripard:
>> The bind hooks will modify their controller registers, so simplefb is
>> going to be unusable anyway. Let's avoid any transient state where it
>> could still be in the system but no longer functionnal.
>>
>> Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>> ---
>>   drivers/gpu/drm/vc4/vc4_drv.c | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/vc4/vc4_drv.c 
>> b/drivers/gpu/drm/vc4/vc4_drv.c
>> index 16abc3a3d601..8ab89f805826 100644
>> --- a/drivers/gpu/drm/vc4/vc4_drv.c
>> +++ b/drivers/gpu/drm/vc4/vc4_drv.c
>> @@ -251,6 +251,10 @@ static int vc4_drm_bind(struct device *dev)
> 
> Since you work on this, I'd like to suggest to call 
> drm_firmware_drivers_only() at the very top of this function. It's our 
> new interface for the kernel's nomodeset argument. If it returns false, 

s/false/true

> the user has disabled native drivers for this boot. The generic DRM 
> driver will continue to run the device.
> 
>>       if (ret)
>>           return ret;
>> +    ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
>> +    if (ret)
>> +        return ret;
>> +
> 
> There's quite a bit of work being done before calling this function. 
> None of it is allowed to touch HW.
> 
> Is that reliable? If so, the code is fine, otherwise the call should go 
> to the top of the function.
> 
> Best regards
> Thomas
> 
>>       ret = component_bind_all(dev, drm);
>>       if (ret)
>>           return ret;
>> @@ -259,10 +263,6 @@ static int vc4_drm_bind(struct device *dev)
>>       if (ret)
>>           goto unbind_all;
>> -    ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
>> -    if (ret)
>> -        goto unbind_all;
>> -
>>       ret = vc4_kms_load(drm);
>>       if (ret < 0)
>>           goto unbind_all;
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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Re: [PATCH v3 2/3] drm/vc4: Remove conflicting framebuffers before callind bind_all

[Thomas Zimmermann]

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Am 13.12.21 um 10:47 schrieb Thomas Zimmermann:
> Hi Maxime
> 
> Am 13.12.21 um 10:25 schrieb Maxime Ripard:
>> The bind hooks will modify their controller registers, so simplefb is
>> going to be unusable anyway. Let's avoid any transient state where it
>> could still be in the system but no longer functionnal.
>>
>> Acked-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>> ---
>>   drivers/gpu/drm/vc4/vc4_drv.c | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/vc4/vc4_drv.c 
>> b/drivers/gpu/drm/vc4/vc4_drv.c
>> index 16abc3a3d601..8ab89f805826 100644
>> --- a/drivers/gpu/drm/vc4/vc4_drv.c
>> +++ b/drivers/gpu/drm/vc4/vc4_drv.c
>> @@ -251,6 +251,10 @@ static int vc4_drm_bind(struct device *dev)
> 
> Since you work on this, I'd like to suggest to call 
> drm_firmware_drivers_only() at the very top of this function. It's our 
> new interface for the kernel's nomodeset argument. If it returns false, 

s/false/true

> the user has disabled native drivers for this boot. The generic DRM 
> driver will continue to run the device.
> 
>>       if (ret)
>>           return ret;
>> +    ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
>> +    if (ret)
>> +        return ret;
>> +
> 
> There's quite a bit of work being done before calling this function. 
> None of it is allowed to touch HW.
> 
> Is that reliable? If so, the code is fine, otherwise the call should go 
> to the top of the function.
> 
> Best regards
> Thomas
> 
>>       ret = component_bind_all(dev, drm);
>>       if (ret)
>>           return ret;
>> @@ -259,10 +263,6 @@ static int vc4_drm_bind(struct device *dev)
>>       if (ret)
>>           goto unbind_all;
>> -    ret = drm_aperture_remove_framebuffers(false, &vc4_drm_driver);
>> -    if (ret)
>> -        goto unbind_all;
>> -
>>       ret = vc4_kms_load(drm);
>>       if (ret < 0)
>>           goto unbind_all;
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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