Re: [PATCH v5 2/8] drm/amd/display: use drmm_writeback_connector_init()

[John Harrison]

Ping @Dmitry - is there any progress with this patch set?

Thanks,
John.

On 5/26/26 11:46, Alex Hung wrote:

Will allocating wbcon with drmm_kzalloc before calling amdgpu_dm_wb_connector_init be more memory-safe as below?

@@ -5790,7 +5791,8 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)

         link = dc_get_link_at_index(dm->dc, i);

         if (link->connector_signal == SIGNAL_TYPE_VIRTUAL) {
-            struct amdgpu_dm_wb_connector *wbcon = kzalloc_obj(*wbcon);
+            struct amdgpu_dm_wb_connector *wbcon =

+                drmm_kzalloc(adev_to_drm(adev), sizeof(*wbcon), GFP_KERNEL);

             if (!wbcon) {

                 drm_err(adev_to_drm(adev), "KMS: Failed to allocate writeback connector\n"); @@ -5799,7 +5801,6 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)

             if (amdgpu_dm_wb_connector_init(dm, wbcon, i)) {

                 drm_err(adev_to_drm(adev), "KMS: Failed to initialize writeback connector\n");

-                kfree(wbcon);
                 continue;
             }

On 5/4/26 18:24, Dmitry Baryshkov wrote:

The driver uses drm_writeback_connector_init() instead of its drmm
counterpart, but it doesn't perform the job queue cleanup (neither
manually nor by calling drm_writeback_connector_cleanup()). On the
contrary, the drmm_writeback_connector_init() function ensures the
proper cleanup of the job queue.

Use drmm_plain_encoder_alloc() to allocate simple encoder and
drmm_writeback_connector_init() in order to initialize writeback
connector instance.

Reviewed-by: Louis Chauvet <louis.chau...@bootlin.com>
Reviewed-by: Suraj Kandpal <suraj.kand...@intel.com>
Signed-off-by: Dmitry Baryshkov <dmitry.barysh...@oss.qualcomm.com>
---
  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c    |  2 +-

  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_wb.c | 18 +++++++++++++-----

  2 files changed, 14 insertions(+), 6 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 e96a12ff2d31..2ac64495cdb7 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -10683,7 +10683,7 @@ static void dm_set_writeback(struct amdgpu_display_manager *dm,

          return;
      }
  -    acrtc = to_amdgpu_crtc(wb_conn->encoder.crtc);
+    acrtc = to_amdgpu_crtc(crtc_state->base.crtc);
      if (!acrtc) {
          drm_err(adev_to_drm(adev), "no amdgpu_crtc found\n");
          kfree(wb_info);

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 110f0173eee6..fdc3da40452f 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

@@ -169,7 +169,6 @@ static const struct drm_encoder_helper_funcs amdgpu_dm_wb_encoder_helper_funcs =     static const struct drm_connector_funcs amdgpu_dm_wb_connector_funcs = {

      .fill_modes = drm_helper_probe_single_connector_modes,
-    .destroy = drm_connector_cleanup,
      .reset = amdgpu_dm_connector_funcs_reset,

      .atomic_duplicate_state = amdgpu_dm_connector_atomic_duplicate_state,

      .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,

@@ -188,17 +187,26 @@ int amdgpu_dm_wb_connector_init(struct amdgpu_display_manager *dm,

      struct dc *dc = dm->dc;
      struct dc_link *link = dc_get_link_at_index(dc, link_index);
      int res = 0;
+    struct drm_encoder *encoder;
+
+    encoder = drmm_plain_encoder_alloc(&dm->adev->ddev, NULL,
+                       DRM_MODE_ENCODER_VIRTUAL, NULL);
+    if (IS_ERR(encoder))
+        return PTR_ERR(encoder);
+

+    drm_encoder_helper_add(encoder, &amdgpu_dm_wb_encoder_helper_funcs);

+

+    encoder->possible_crtcs = amdgpu_dm_get_encoder_crtc_mask(dm->adev);

        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,
+    res = drmm_writeback_connector_init(&dm->adev->ddev, &wbcon->base,
                          &amdgpu_dm_wb_connector_funcs,
-                        &amdgpu_dm_wb_encoder_helper_funcs,
+                        encoder,
                          amdgpu_dm_wb_formats,
-                        ARRAY_SIZE(amdgpu_dm_wb_formats),
- amdgpu_dm_get_encoder_crtc_mask(dm->adev));
+                        ARRAY_SIZE(amdgpu_dm_wb_formats));
        if (res)
          return res;