kfree() checks this automatically.

Signed-off-by: Lyude Paul lyude@redhat.com --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 185bf0e2bda2..a398ddd1f306 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -144,10 +144,8 @@ dm_dp_mst_connector_destroy(struct drm_connector *connector) struct amdgpu_dm_connector *amdgpu_dm_connector = to_amdgpu_dm_connector(connector); struct amdgpu_encoder *amdgpu_encoder = amdgpu_dm_connector->mst_encoder;

- if (amdgpu_dm_connector->edid) { - kfree(amdgpu_dm_connector->edid); - amdgpu_dm_connector->edid = NULL; - } + kfree(amdgpu_dm_connector->edid); + amdgpu_dm_connector->edid = NULL;

drm_encoder_cleanup(&amdgpu_encoder->base); kfree(amdgpu_encoder);

We are supposed to be atomic after all. We'll need this in a moment for the next commit.

Signed-off-by: Lyude Paul lyude@redhat.com --- .../drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index a398ddd1f306..d9113ce0be09 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -243,17 +243,17 @@ static int dm_dp_mst_get_modes(struct drm_connector *connector) return ret; }

-static struct drm_encoder *dm_mst_best_encoder(struct drm_connector *connector) +static struct drm_encoder * +dm_mst_atomic_best_encoder(struct drm_connector *connector, + struct drm_connector_state *connector_state) { - struct amdgpu_dm_connector *amdgpu_dm_connector = to_amdgpu_dm_connector(connector); - - return &amdgpu_dm_connector->mst_encoder->base; + return &to_amdgpu_dm_connector(connector)->mst_encoder->base; }

static const struct drm_connector_helper_funcs dm_dp_mst_connector_helper_funcs = { .get_modes = dm_dp_mst_get_modes, .mode_valid = amdgpu_dm_connector_mode_valid, - .best_encoder = dm_mst_best_encoder, + .atomic_best_encoder = dm_mst_atomic_best_encoder, };

static void amdgpu_dm_encoder_destroy(struct drm_encoder *encoder)

While this commit certainly will result in creating less fake MST encoders, the main purpose of this is actually to fix amdgpu's incorrect usage of the drm_encoder API in it's MST code. Currently we create one encoder per-MST connector. However, MST connectors can and usually do get created at basically any point before or after driver device registration. Thus, this means we've been creating and destroying drm_encoder structs every time we create or destroy an MST connector.

This behavior likely is just leftover from when we made amdgpu stop reusing DRM connectors for MST. Since this will definitely break things, let's fix it by being a bit more efficient with our MST encoders by creating one per-CRTC, which allows us to have just the right number of encoders and do so before we've called drm_dev_register().

Signed-off-by: Lyude Paul lyude@redhat.com Fixes: 0e6613e46fed ("drm/amd/display: Drop reusing drm connector for MST") Cc: Harry Wentland harry.wentland@amd.com Cc: Lyude Paul lyude@redhat.com Cc: Alex Deucher alexander.deucher@amd.com Cc: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Cc: Leo Li sunpeng.li@amd.com Cc: David Francis David.Francis@amd.com Cc: "Jerry (Fangzhi) Zuo" Jerry.Zuo@amd.com Cc: Mario Kleiner mario.kleiner.de@gmail.com Cc: Thomas Lim Thomas.Lim@amd.com Cc: "Mathias Fröhlich" Mathias.Froehlich@web.de Cc: stable@vger.kernel.org # v4.20+ --- drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h | 3 ++ .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 4 +++ .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 1 - .../display/amdgpu_dm/amdgpu_dm_mst_types.c | 28 ++++++++++--------- .../display/amdgpu_dm/amdgpu_dm_mst_types.h | 3 ++ 5 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h index eb9975f4decb..b54a6f4e392e 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h @@ -427,6 +427,9 @@ struct amdgpu_crtc {

int otg_inst; struct drm_pending_vblank_event *event; + + /* Fake encoder to use for MST */ + struct amdgpu_encoder *mst_encoder; };

struct amdgpu_encoder_atom_dig { 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 f4e0f27a76de..b404f1ae6df7 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -4803,6 +4803,10 @@ static int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm, true, MAX_COLOR_LUT_ENTRIES); drm_mode_crtc_set_gamma_size(&acrtc->base, MAX_COLOR_LEGACY_LUT_ENTRIES);

+ acrtc->mst_encoder = amdgpu_dm_dp_create_fake_mst_encoder(acrtc); + if (!acrtc->mst_encoder) + goto fail; + return 0;

fail: 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 c8c525a2b505..bcd9115c4923 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h @@ -267,7 +267,6 @@ struct amdgpu_dm_connector { struct amdgpu_dm_dp_aux dm_dp_aux; struct drm_dp_mst_port *port; struct amdgpu_dm_connector *mst_port; - struct amdgpu_encoder *mst_encoder;

/* TODO see if we can merge with ddc_bus or make a dm_connector */ struct amdgpu_i2c_adapter *i2c; diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index d9113ce0be09..d680f32cf625 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -141,14 +141,12 @@ dm_dp_mst_detect(struct drm_connector *connector, bool force) static void dm_dp_mst_connector_destroy(struct drm_connector *connector) { - struct amdgpu_dm_connector *amdgpu_dm_connector = to_amdgpu_dm_connector(connector); - struct amdgpu_encoder *amdgpu_encoder = amdgpu_dm_connector->mst_encoder; + struct amdgpu_dm_connector *amdgpu_dm_connector = + to_amdgpu_dm_connector(connector);

kfree(amdgpu_dm_connector->edid); amdgpu_dm_connector->edid = NULL;

- drm_encoder_cleanup(&amdgpu_encoder->base); - kfree(amdgpu_encoder); drm_connector_cleanup(connector); drm_dp_mst_put_port_malloc(amdgpu_dm_connector->port); kfree(amdgpu_dm_connector); @@ -247,7 +245,7 @@ static struct drm_encoder * dm_mst_atomic_best_encoder(struct drm_connector *connector, struct drm_connector_state *connector_state) { - return &to_amdgpu_dm_connector(connector)->mst_encoder->base; + return &to_amdgpu_crtc(connector_state->crtc)->mst_encoder->base; }

static const struct drm_connector_helper_funcs dm_dp_mst_connector_helper_funcs = { @@ -266,11 +264,10 @@ static const struct drm_encoder_funcs amdgpu_dm_encoder_funcs = { .destroy = amdgpu_dm_encoder_destroy, };

-static struct amdgpu_encoder * -dm_dp_create_fake_mst_encoder(struct amdgpu_dm_connector *connector) +struct amdgpu_encoder * +amdgpu_dm_dp_create_fake_mst_encoder(struct amdgpu_crtc *acrtc) { - struct drm_device *dev = connector->base.dev; - struct amdgpu_device *adev = dev->dev_private; + struct drm_device *dev = acrtc->base.dev; struct amdgpu_encoder *amdgpu_encoder; struct drm_encoder *encoder;

@@ -279,7 +276,7 @@ dm_dp_create_fake_mst_encoder(struct amdgpu_dm_connector *connector) return NULL;

encoder = &amdgpu_encoder->base; - encoder->possible_crtcs = amdgpu_dm_get_encoder_crtc_mask(adev); + encoder->possible_crtcs = drm_crtc_mask(&acrtc->base);

drm_encoder_init( dev, @@ -302,6 +299,7 @@ dm_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr, struct drm_device *dev = master->base.dev; struct amdgpu_device *adev = dev->dev_private; struct amdgpu_dm_connector *aconnector; + struct drm_crtc *crtc; struct drm_connector *connector;

aconnector = kzalloc(sizeof(*aconnector), GFP_KERNEL); @@ -329,9 +327,13 @@ dm_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr, master->dc_link, master->connector_id);

- aconnector->mst_encoder = dm_dp_create_fake_mst_encoder(master); - drm_connector_attach_encoder(&aconnector->base, - &aconnector->mst_encoder->base); + /* Attach fake MST encoders */ + drm_for_each_crtc(crtc, dev) { + struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc); + + drm_connector_attach_encoder(connector, + &acrtc->mst_encoder->base); + }

drm_object_attach_property( &connector->base, diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h index 2da851b40042..ce84d9db83e5 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h @@ -28,8 +28,11 @@

struct amdgpu_display_manager; struct amdgpu_dm_connector; +struct amdgpu_crtc;

void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm, struct amdgpu_dm_connector *aconnector); +struct amdgpu_encoder * +amdgpu_dm_dp_create_fake_mst_encoder(struct amdgpu_crtc *acrtc);

#endif

Turns out that we don't actually check this anywhere, and additionally actually forget to even mention this in our documentation.

Since we've had one driver making this mistake already, let's clarify this by mentioning this limitation in the kernel docs. Additionally, for drivers not using the legacy ->load/->unload() hooks (which make it impossible to create all encoders before registration): print a big warning when drm_encoder_init() is called after device registration, or when drm_encoder_cleanup() is called before device unregistration.

Signed-off-by: Lyude Paul lyude@redhat.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com --- drivers/gpu/drm/drm_encoder.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c index 80d88a55302e..5c5e40aafa4e 100644 --- a/drivers/gpu/drm/drm_encoder.c +++ b/drivers/gpu/drm/drm_encoder.c @@ -99,9 +99,12 @@ void drm_encoder_unregister_all(struct drm_device *dev) * @encoder_type: user visible type of the encoder * @name: printf style format string for the encoder name, or NULL for default name * - * Initialises a preallocated encoder. Encoder should be subclassed as part of - * driver encoder objects. At driver unload time drm_encoder_cleanup() should be - * called from the driver's &drm_encoder_funcs.destroy hook. + * Initialises a preallocated encoder. The encoder should be subclassed as + * part of driver encoder objects. This function may not be called after the + * device is registered with drm_dev_register(). + * + * At driver unload time drm_encoder_cleanup() must be called from the + * driver's &drm_encoder_funcs.destroy hook. * * Returns: * Zero on success, error code on failure. @@ -117,6 +120,14 @@ int drm_encoder_init(struct drm_device *dev, if (WARN_ON(dev->mode_config.num_encoder >= 32)) return -EINVAL;

+ /* + * Encoders should never be added after device registration, with the + * exception of drivers using the legacy load/unload callbacks where + * it's impossible to create encoders beforehand. Such drivers should + * convert to using drm_dev_register() and friends. + */ + WARN_ON(dev->registered && !dev->driver->load); + ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER); if (ret) return ret; @@ -155,16 +166,22 @@ EXPORT_SYMBOL(drm_encoder_init); * drm_encoder_cleanup - cleans up an initialised encoder * @encoder: encoder to cleanup * - * Cleans up the encoder but doesn't free the object. + * Cleans up the encoder but doesn't free the object. This function may not be + * called until the respective &struct drm_device has been unregistered from + * userspace using drm_dev_unregister(). */ void drm_encoder_cleanup(struct drm_encoder *encoder) { struct drm_device *dev = encoder->dev;

- /* Note that the encoder_list is considered to be static; should we - * remove the drm_encoder at runtime we would have to decrement all - * the indices on the drm_encoder after us in the encoder_list. + /* + * Encoders should never be removed after device registration, with + * the exception of drivers using the legacy load/unload callbacks + * where it's impossible to remove encoders until after + * deregistration. Such drivers should convert to using + * drm_dev_register() and friends. */ + WARN_ON(dev->registered && !dev->driver->unload);

if (encoder->bridge) { struct drm_bridge *bridge = encoder->bridge;