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drm/exynos: dsi: Fix bridge chain handling
Commit05193dc381
("drm/bridge: Make the bridge chain a double-linked list") patched the bridge chain logic to use a double-linked list instead of a single-linked list. This change induced changes to the Exynos driver which was manually resetting the encoder->bridge element to NULL to control the enable/disable sequence of the bridge chain. During this conversion, 2 bugs were introduced: 1/ list_splice() was used to move chain elements to our own internal chain, but list_splice() does not reset the source list to an empty state, leading to unexpected bridge hook calls when drm_bridge_chain_xxx() helpers were called by the core. Replacing the list_splice() call by list_splice_init() fixes this problem. 2/ drm_bridge_chain_xxx() helpers operate on the bridge->encoder->bridge_chain list, which is now empty. When the helper uses list_for_each_entry_reverse() we end up with no operation done which is not what we want. But that's even worse when the helper uses list_for_each_entry_from(), because in that case we end up in an infinite loop searching for the list head element which is no longer encoder->bridge_chain but exynos_dsi->bridge_chain. To address that problem we stop using the bridge chain helpers and call the hooks directly. Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Fixes:05193dc381
("drm/bridge: Make the bridge chain a double-linked list") Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191227144124.210294-3-boris.brezillon@collabora.com
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parent
033bfe7538
commit
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1 changed files with 24 additions and 5 deletions
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@ -1378,6 +1378,7 @@ static void exynos_dsi_unregister_te_irq(struct exynos_dsi *dsi)
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static void exynos_dsi_enable(struct drm_encoder *encoder)
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{
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struct exynos_dsi *dsi = encoder_to_dsi(encoder);
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struct drm_bridge *iter;
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int ret;
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if (dsi->state & DSIM_STATE_ENABLED)
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@ -1391,7 +1392,11 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
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if (ret < 0)
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goto err_put_sync;
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} else {
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drm_bridge_chain_pre_enable(dsi->out_bridge);
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list_for_each_entry_reverse(iter, &dsi->bridge_chain,
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chain_node) {
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if (iter->funcs->pre_enable)
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iter->funcs->pre_enable(iter);
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}
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}
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exynos_dsi_set_display_mode(dsi);
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@ -1402,7 +1407,10 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
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if (ret < 0)
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goto err_display_disable;
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} else {
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drm_bridge_chain_enable(dsi->out_bridge);
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list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {
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if (iter->funcs->enable)
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iter->funcs->enable(iter);
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}
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}
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dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
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@ -1420,6 +1428,7 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
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static void exynos_dsi_disable(struct drm_encoder *encoder)
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{
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struct exynos_dsi *dsi = encoder_to_dsi(encoder);
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struct drm_bridge *iter;
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if (!(dsi->state & DSIM_STATE_ENABLED))
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return;
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@ -1427,10 +1436,20 @@ static void exynos_dsi_disable(struct drm_encoder *encoder)
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dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
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drm_panel_disable(dsi->panel);
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drm_bridge_chain_disable(dsi->out_bridge);
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list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) {
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if (iter->funcs->disable)
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iter->funcs->disable(iter);
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}
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exynos_dsi_set_display_enable(dsi, false);
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drm_panel_unprepare(dsi->panel);
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drm_bridge_chain_post_disable(dsi->out_bridge);
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list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {
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if (iter->funcs->post_disable)
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iter->funcs->post_disable(iter);
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}
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dsi->state &= ~DSIM_STATE_ENABLED;
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pm_runtime_put_sync(dsi->dev);
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}
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@ -1523,7 +1542,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
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if (out_bridge) {
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drm_bridge_attach(encoder, out_bridge, NULL);
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dsi->out_bridge = out_bridge;
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list_splice(&encoder->bridge_chain, &dsi->bridge_chain);
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list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain);
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} else {
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int ret = exynos_dsi_create_connector(encoder);
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