display: embed the writeback encoder in amdgpu_dm_wb_connector

Harry Wentland Tue, 20 Oct 2026 12:14:56 -0700

On 10/19/26 09:12, Dmitry Baryshkov wrote:

drm_writeback_connector_init() hides the encoder inside struct
drm_writeback_connector, which is the only reason that structure carries
an encoder at all. Every other writeback user already owns its encoder.


Embed the encoder in the driver's own structure and register the
connector with drm_writeback_connector_init_with_encoder(), so that the
encoder can be dropped from drm_writeback_connector.

Assisted-by: LLM
Signed-off-by: Dmitry Baryshkov <[email protected]>


Reviewed-by: Harry Wentland <[email protected]>

Harry

---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c  |  2 +-
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h  |  1 +
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c   | 29 ++++++++++++++++------
 .../amd/display/amdgpu_dm/tests/amdgpu_dm_test.c   |  4 +--
 .../display/amdgpu_dm/tests/amdgpu_dm_wb_test.c    |  4 +--
 5 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 5e106b65034d..07dd69b42e83 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4805,7 +4805,7 @@ dm_set_writeback(struct amdgpu_display_manager *dm,
                goto cleanup;
        }

- acrtc = to_amdgpu_crtc(wb_conn->encoder.crtc);

+       acrtc = 
to_amdgpu_crtc(to_amdgpu_dm_wb_connector(wb_conn)->encoder.crtc);
        if (!acrtc) {
                drm_err(adev_to_drm(adev), "no amdgpu_crtc found\n");
                goto cleanup;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 1d256dce0e4b..d365370d9958 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -930,6 +930,7 @@ static inline void amdgpu_dm_set_mst_status(uint8_t *status,

struct amdgpu_dm_wb_connector {

        struct drm_writeback_connector base;
+       struct drm_encoder encoder;
        struct dc_link *link;
 };

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c

index 6f91a992d43f..b5b186e4f81c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c
@@ -218,6 +218,10 @@ STATIC_IFN_KUNIT void amdgpu_dm_wb_cleanup_job(struct 
drm_writeback_connector *c
 }
 EXPORT_IF_KUNIT(amdgpu_dm_wb_cleanup_job);

+static const struct drm_encoder_funcs amdgpu_dm_wb_encoder_funcs = {

+       .destroy = drm_encoder_cleanup,
+};
+
 static const struct drm_encoder_helper_funcs amdgpu_dm_wb_encoder_helper_funcs 
= {
        .atomic_check = amdgpu_dm_wb_encoder_atomic_check,
 };
@@ -246,17 +250,26 @@ int amdgpu_dm_wb_connector_init(struct 
amdgpu_display_manager *dm,

wbcon->link = link;- drm_connector_helper_add(&wbcon->base.base, &amdgpu_dm_wb_conn_helper_funcs);

-
-       res = drm_writeback_connector_init(&dm->adev->ddev, &wbcon->base,
-                                           &amdgpu_dm_wb_connector_funcs,
-                                           &amdgpu_dm_wb_encoder_helper_funcs,
-                                           amdgpu_dm_wb_formats,
-                                           ARRAY_SIZE(amdgpu_dm_wb_formats),
-                                           
amdgpu_dm_get_encoder_crtc_mask(dm->adev));
+       drm_encoder_helper_add(&wbcon->encoder, 
&amdgpu_dm_wb_encoder_helper_funcs);
+       wbcon->encoder.possible_crtcs = 
amdgpu_dm_get_encoder_crtc_mask(dm->adev);

+ res = drm_encoder_init(&dm->adev->ddev, &wbcon->encoder,

+                              &amdgpu_dm_wb_encoder_funcs,
+                              DRM_MODE_ENCODER_VIRTUAL, NULL);
        if (res)
                return res;
+
+       drm_connector_helper_add(&wbcon->base.base, 
&amdgpu_dm_wb_conn_helper_funcs);
+
+       res = drm_writeback_connector_init_with_encoder(&dm->adev->ddev, 
&wbcon->base,
+                                                       &wbcon->encoder,
+                                                       
&amdgpu_dm_wb_connector_funcs,
+                                                       amdgpu_dm_wb_formats,
+                                                       
ARRAY_SIZE(amdgpu_dm_wb_formats));
+       if (res) {
+               drm_encoder_cleanup(&wbcon->encoder);
+               return res;
+       }
        /*
         * Some of the properties below require access to state, like bpc.
         * Allocate some default initial connector state with our reset helper.
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
index e27f6e504395..9d237f2db95c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_test.c
@@ -4535,7 +4535,7 @@ static void dm_test_clear_writeback_removes_stream(struct 
kunit *test)
 static void dm_test_set_writeback_no_pipe(struct kunit *test)
 {
        struct amdgpu_device *adev = dm_kunit_alloc_adev(test);
-       struct drm_writeback_connector *wb_conn;
+       struct amdgpu_dm_wb_connector *wb_conn;
        struct drm_connector_state *conn_state;
        struct drm_writeback_job *job;
        struct amdgpu_framebuffer *afb;
@@ -4565,7 +4565,7 @@ static void dm_test_set_writeback_no_pipe(struct kunit 
*test)
        conn_state->writeback_job = job;
        crtc_state->stream = dm_kunit_alloc_stream(test, NULL);

- dm_set_writeback(&adev->dm, crtc_state, &wb_conn->base, conn_state);

+       dm_set_writeback(&adev->dm, crtc_state, &wb_conn->base.base, 
conn_state);

KUNIT_EXPECT_NULL(test, acrtc->wb_conn);

        KUNIT_EXPECT_FALSE(test, acrtc->wb_pending);
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
index 03036f906385..2711696f6b9c 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
@@ -506,8 +506,8 @@ static void dm_test_wb_connector_init_success(struct kunit 
*test)
        KUNIT_EXPECT_TRUE(test, wbcon->base.base.funcs != NULL);
        KUNIT_EXPECT_TRUE(test, wbcon->base.base.helper_private != NULL);
        KUNIT_EXPECT_TRUE(test, wbcon->base.base.state != NULL);
-       KUNIT_EXPECT_TRUE(test, wbcon->base.encoder.funcs != NULL);
-       KUNIT_EXPECT_EQ(test, wbcon->base.encoder.possible_crtcs, 0x1);
+       KUNIT_EXPECT_TRUE(test, wbcon->encoder.funcs != NULL);
+       KUNIT_EXPECT_EQ(test, wbcon->encoder.possible_crtcs, 0x1);
 }

/* Tests for amdgpu_dm_wb_prepare_job / amdgpu_dm_wb_cleanup_job */

Re: [PATCH v7 1/9] drm/amd/display: embed the writeback encoder in amdgpu_dm_wb_connector

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