Hi,
On 25/10/2019 15:29, Neil Armstrong wrote:
> On 23/10/2019 17:44, Boris Brezillon wrote:
>> So that each element in the chain can easily access its predecessor.
>> This will be needed to support bus format negotiation between elements
>> of the bridge chain.
>>
>> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
>> ---
>> Changes in v3:
>> * None
>>
>> Changes in v2:
>> * Adjust things to the "dummy encoder bridge" change (patch 2 in this
>> series)
>> ---
>> drivers/gpu/drm/drm_bridge.c | 171 ++++++++++++++++++++++------------
>> drivers/gpu/drm/drm_encoder.c | 16 +---
>> include/drm/drm_bridge.h | 12 ++-
>> include/drm/drm_encoder.h | 9 +-
>> 4 files changed, 135 insertions(+), 73 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
>> index 54c874493c57..c5cf8a9c4237 100644
>> --- a/drivers/gpu/drm/drm_bridge.c
>> +++ b/drivers/gpu/drm/drm_bridge.c
[...]
>>
>> @@ -426,15 +471,23 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
>> void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
>> struct drm_atomic_state *state)
>> {
>> + struct drm_encoder *encoder;
>> + struct drm_bridge *iter;
>> +
>> if (!bridge)
>> return;
>>
>> - drm_atomic_bridge_chain_pre_enable(bridge->next, state);
>> + encoder = bridge->encoder;
>> + list_for_each_entry_reverse(iter, &bridge->encoder->bridge_chain,
>> + chain_node) {
This should use the encoder local variable in list_for_each_entry_reverse()
>> + if (iter->funcs->atomic_pre_enable)
>> + iter->funcs->atomic_pre_enable(iter, state);
>> + else if (iter->funcs->pre_enable)
>> + iter->funcs->pre_enable(iter);
>>
>> - if (bridge->funcs->atomic_pre_enable)
>> - bridge->funcs->atomic_pre_enable(bridge, state);
>> - else if (bridge->funcs->pre_enable)
>> - bridge->funcs->pre_enable(bridge);
>> + if (iter == bridge)
>> + break;
>> + }
>> }
>> EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);
>>
>> @@ -453,15 +506,19 @@ EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);
>> void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
>> struct drm_atomic_state *state)
>> {
>> + struct drm_encoder *encoder;
>> +
>> if (!bridge)
>> return;
>>
>> - if (bridge->funcs->atomic_enable)
>> - bridge->funcs->atomic_enable(bridge, state);
>> - else if (bridge->funcs->enable)
>> - bridge->funcs->enable(bridge);
>> -
>> - drm_atomic_bridge_chain_enable(bridge->next, state);
>> + encoder = bridge->encoder;
>> + list_for_each_entry_from(bridge, &bridge->encoder->bridge_chain,
>> + chain_node) {
This should use encoder instead of bridge->encoder otherwise bridge will
change and bridge->encoder->bridge_chain won't be valid during the for_each and
cause the following :
[ 79.082861] WARNING: CPU: 2 PID: 1999 at drivers/gpu/drm/drm_bridge.c:607 drm_atomic_bridge_chain_enable+0xac/0xc0
...
[ 79.210153] drm_atomic_bridge_chain_enable+0xac/0xc0
[ 79.215156] drm_atomic_helper_commit_modeset_enables+0x138/0x248
[ 79.221190] drm_atomic_helper_commit_tail_rpm+0x2c/0x78
[ 79.226452] commit_tail+0x50/0xc0
[ 79.229815] drm_atomic_helper_commit+0xe8/0x168
[ 79.234386] drm_atomic_commit+0x48/0x58
[ 79.238269] drm_client_modeset_commit_atomic.isra.15+0x184/0x220
[ 79.244305] drm_client_modeset_commit_force+0x64/0x1a0
[ 79.249482] drm_fb_helper_restore_fbdev_mode_unlocked+0x70/0xe8
[ 79.255432] drm_fbdev_client_restore+0x14/0x20
[ 79.259920] drm_client_dev_restore+0x80/0xd8
[ 79.264231] drm_lastclose+0x4c/0x58
[ 79.267765] drm_release+0xa8/0x178
>> + if (bridge->funcs->atomic_enable)
>> + bridge->funcs->atomic_enable(bridge, state);
>> + else if (bridge->funcs->enable)
>> + bridge->funcs->enable(bridge);
>> + }
>> }
>> EXPORT_SYMBOL(drm_atomic_bridge_chain_enable);
>>
>> diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
>> index 4fe9e723e227..e555281f43d4 100644
>> --- a/drivers/gpu/drm/drm_encoder.c
>> +++ b/drivers/gpu/drm/drm_encoder.c
>> @@ -140,6 +140,7 @@ int drm_encoder_init(struct drm_device *dev,
>> goto out_put;
>> }
>>
>> + INIT_LIST_HEAD(&encoder->bridge_chain);
>> list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
>> encoder->index = dev->mode_config.num_encoder++;
>>
>> @@ -160,23 +161,16 @@ EXPORT_SYMBOL(drm_encoder_init);
>> void drm_encoder_cleanup(struct drm_encoder *encoder)
>> {
>> struct drm_device *dev = encoder->dev;
>> + struct drm_bridge *bridge, *next;
>>
>> /* 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.
>> */
>>
>> - if (encoder->bridge) {
>> - struct drm_bridge *bridge;
>> - struct drm_bridge *next;
>> -
>> - bridge = drm_bridge_chain_get_first_bridge(encoder);
>> - while (bridge) {
>> - next = bridge->next;
>> - drm_bridge_detach(bridge);
>> - bridge = next;
>> - }
>> - }
>> + list_for_each_entry_safe(bridge, next, &encoder->bridge_chain,
>> + chain_node)
>> + drm_bridge_detach(bridge);
>>
>> drm_mode_object_unregister(dev, &encoder->base);
>> kfree(encoder->name);
>> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
>> index 27eef63ce0ff..3ab16c95e59e 100644
>> --- a/include/drm/drm_bridge.h
>> +++ b/include/drm/drm_bridge.h
>> @@ -384,8 +384,8 @@ struct drm_bridge {
>> struct drm_device *dev;
>> /** @encoder: encoder to which this bridge is connected */
>> struct drm_encoder *encoder;
>> - /** @next: the next bridge in the encoder chain */
>> - struct drm_bridge *next;
>> + /** @chain_node: used to form a bridge chain */
>> + struct list_head chain_node;
>> #ifdef CONFIG_OF
>> /** @of_node: device node pointer to the bridge */
>> struct device_node *of_node;
>> @@ -420,7 +420,10 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
>> static inline struct drm_bridge *
>> drm_bridge_chain_get_next_bridge(struct drm_bridge *bridge)
>> {
>> - return bridge->next;
>> + if (list_is_last(&bridge->chain_node, &bridge->encoder->bridge_chain))
>> + return NULL;
>> +
>> + return list_next_entry(bridge, chain_node);
>> }
>>
>> /**
>> @@ -434,7 +437,8 @@ drm_bridge_chain_get_next_bridge(struct drm_bridge *bridge)
>> static inline struct drm_bridge *
>> drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
>> {
>> - return encoder->bridge;
>> + return list_first_entry_or_null(&encoder->bridge_chain,
>> + struct drm_bridge, chain_node);
>> }
>>
>> bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
>> diff --git a/include/drm/drm_encoder.h b/include/drm/drm_encoder.h
>> index f06164f44efe..9b3dde177c81 100644
>> --- a/include/drm/drm_encoder.h
>> +++ b/include/drm/drm_encoder.h
>> @@ -172,7 +172,14 @@ struct drm_encoder {
>> * &drm_connector_state.crtc.
>> */
>> struct drm_crtc *crtc;
>> - struct drm_bridge *bridge;
>> +
>> + /**
>> + * @bridge_chain: Bridges attached to this encoder. The first entry of
>> + * this list is always &drm_encoder.bridge. It may be followed by other
>> + * bridge entities.
>> + */
>> + struct list_head bridge_chain;
>> +
>> const struct drm_encoder_funcs *funcs;
>> const struct drm_encoder_helper_funcs *helper_private;
>> };
>>
>
> Reviewed-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>
With these fixed, you can keep my Reviewed-by
Neil
