[PATCH] drm/virtio: inline drm_simple_encoder_init()

[PATCH] drm/virtio: inline drm_simple_encoder_init()

[Melih Emik]

The helper drm_simple_encoder_init() is deprecated because it adds an
unnecessary intermediate layer between atomic modesetting and DRM drivers,
as documented in Documentation/gpu/todo.rst.

Inline the functionality by calling drm_encoder_init() directly with a
local instance of struct drm_encoder_funcs. This allows removing the
dependency on <drm/drm_simple_kms_helper.h> in favor of
<drm/drm_encoder.h>.

Signed-off-by: Melih Emik <melihemik@noirlang.tr>
---
Tested:
- Compiled with W=1 on x86_64 with zero warnings or errors.
- Verified with lockdep and debug mutexes enabled
  (CONFIG_PROVE_LOCKING=y, CONFIG_DEBUG_MUTEXES=y).
- Boot-tested full bzImage in QEMU with -device virtio-gpu-pci and
  initcall_debug, confirming successful probe and initialization
  (probe of virtio0 with driver virtio_gpu returned 0) and zero
  lockdep/kernel warnings.
- Verified with scripts/checkpatch.pl (0 errors, 0 warnings).

 drivers/gpu/drm/virtio/virtgpu_display.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_display.c b/drivers/gpu/drm/virtio/virtgpu_display.c
index a1a875a0c706..1bdbf452d111 100644
--- a/drivers/gpu/drm/virtio/virtgpu_display.c
+++ b/drivers/gpu/drm/virtio/virtgpu_display.c
@@ -28,11 +28,11 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_damage_helper.h>
 #include <drm/drm_edid.h>
+#include <drm/drm_encoder.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
-#include <drm/drm_simple_kms_helper.h>
 #include <drm/drm_vblank.h>
 #include <drm/drm_vblank_helper.h>
 
@@ -232,6 +232,10 @@ static enum drm_mode_status virtio_gpu_conn_mode_valid(struct drm_connector *con
 	return MODE_BAD;
 }
 
+static const struct drm_encoder_funcs virtio_gpu_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
 static const struct drm_encoder_helper_funcs virtio_gpu_enc_helper_funcs = {
 	.mode_set   = virtio_gpu_enc_mode_set,
 	.enable     = virtio_gpu_enc_enable,
@@ -306,7 +310,10 @@ static int vgdev_output_init(struct virtio_gpu_device *vgdev, int index)
 	if (vgdev->has_edid)
 		drm_connector_attach_edid_property(connector);
 
-	drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_VIRTUAL);
+	ret = drm_encoder_init(dev, encoder, &virtio_gpu_encoder_funcs,
+			       DRM_MODE_ENCODER_VIRTUAL, NULL);
+	if (ret)
+		return ret;
 	drm_encoder_helper_add(encoder, &virtio_gpu_enc_helper_funcs);
 	encoder->possible_crtcs = 1 << index;
 
-- 
2.56.0

Re: [PATCH] drm/virtio: inline drm_simple_encoder_init()

[Thomas Zimmermann]

Hi

Am 18.10.26 um 13:28 schrieb Melih Emik:
> The helper drm_simple_encoder_init() is deprecated because it adds an
> unnecessary intermediate layer between atomic modesetting and DRM drivers,
> as documented in Documentation/gpu/todo.rst.
>
> Inline the functionality by calling drm_encoder_init() directly with a
> local instance of struct drm_encoder_funcs. This allows removing the
> dependency on <drm/drm_simple_kms_helper.h> in favor of
> <drm/drm_encoder.h>.

These have all been fixed already. You need to work on drm-tip, drm-misc 
or a driver-specific git tree for development.

Best regards
Thomas


>
> Signed-off-by: Melih Emik <melihemik@noirlang.tr>
> ---
> Tested:
> - Compiled with W=1 on x86_64 with zero warnings or errors.
> - Verified with lockdep and debug mutexes enabled
>    (CONFIG_PROVE_LOCKING=y, CONFIG_DEBUG_MUTEXES=y).
> - Boot-tested full bzImage in QEMU with -device virtio-gpu-pci and
>    initcall_debug, confirming successful probe and initialization
>    (probe of virtio0 with driver virtio_gpu returned 0) and zero
>    lockdep/kernel warnings.
> - Verified with scripts/checkpatch.pl (0 errors, 0 warnings).
>
>   drivers/gpu/drm/virtio/virtgpu_display.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_display.c b/drivers/gpu/drm/virtio/virtgpu_display.c
> index a1a875a0c706..1bdbf452d111 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_display.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_display.c
> @@ -28,11 +28,11 @@
>   #include <drm/drm_atomic_helper.h>
>   #include <drm/drm_damage_helper.h>
>   #include <drm/drm_edid.h>
> +#include <drm/drm_encoder.h>
>   #include <drm/drm_fourcc.h>
>   #include <drm/drm_gem_framebuffer_helper.h>
>   #include <drm/drm_print.h>
>   #include <drm/drm_probe_helper.h>
> -#include <drm/drm_simple_kms_helper.h>
>   #include <drm/drm_vblank.h>
>   #include <drm/drm_vblank_helper.h>
>   
> @@ -232,6 +232,10 @@ static enum drm_mode_status virtio_gpu_conn_mode_valid(struct drm_connector *con
>   	return MODE_BAD;
>   }
>   
> +static const struct drm_encoder_funcs virtio_gpu_encoder_funcs = {
> +	.destroy = drm_encoder_cleanup,
> +};
> +
>   static const struct drm_encoder_helper_funcs virtio_gpu_enc_helper_funcs = {
>   	.mode_set   = virtio_gpu_enc_mode_set,
>   	.enable     = virtio_gpu_enc_enable,
> @@ -306,7 +310,10 @@ static int vgdev_output_init(struct virtio_gpu_device *vgdev, int index)
>   	if (vgdev->has_edid)
>   		drm_connector_attach_edid_property(connector);
>   
> -	drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_VIRTUAL);
> +	ret = drm_encoder_init(dev, encoder, &virtio_gpu_encoder_funcs,
> +			       DRM_MODE_ENCODER_VIRTUAL, NULL);
> +	if (ret)
> +		return ret;
>   	drm_encoder_helper_add(encoder, &virtio_gpu_enc_helper_funcs);
>   	encoder->possible_crtcs = 1 << index;
>   

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Stefan Gaiser, Jochen Jaser, Abhinav Puri, (HRB 36809, AG Nürnberg)

Re: [PATCH] drm/virtio: inline drm_simple_encoder_init()

[Melih Emik]

Hi Thomas,

Thanks for the pointer! I will base future DRM work on drm-misc/drm-tip.

Best regards,
Melih