The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 647474b8d980256b26b1cd112d7333a4dbd4260a Mon Sep 17 00:00:00 2001 From: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Date: Mon, 31 Jan 2022 09:55:20 +0100 Subject: [PATCH] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
DRM bridge drivers are now attaching their DSI device at probe time, which requires us to register our DSI host in order to let the bridge to probe: this recently started producing an endless -EPROBE_DEFER loop on some machines that are using external bridges, like the parade-ps8640, found on the ACER Chromebook R13.
Now that the DSI hosts/devices probe sequence is documented, we can do adjustments to the mtk_dsi driver as to both fix now and make sure to avoid this situation in the future: for this, following what is documented in drm_bridge.c, move the mtk_dsi component_add() to the mtk_dsi_ops.attach callback and delete it in the detach callback; keeping in mind that we are registering a drm_bridge for our DSI, which is only used/attached if the DSI Host is bound, it wouldn't make sense to keep adding our bridge at probe time (as it would be useless to have it if mtk_dsi_ops.attach() fails!), so also move that one to the dsi host attach function (and remove it in detach).
Cc: stable@vger.kernel.org # 5.15.x Signed-off-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Reviewed-by: Andrzej Hajda andrzej.hajda@intel.com Reviewed-by: Jagan Teki jagan@amarulasolutions.com Tested-by: Nícolas F. R. A. Prado nfraprado@collabora.com Signed-off-by: Chun-Kuang Hu chunkuang.hu@kernel.org
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c index 5d90d2eb0019..bced4c7d668e 100644 --- a/drivers/gpu/drm/mediatek/mtk_dsi.c +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev) mtk_dsi_poweroff(dsi); }
+static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi) +{ + int ret; + + ret = drm_simple_encoder_init(drm, &dsi->encoder, + DRM_MODE_ENCODER_DSI); + if (ret) { + DRM_ERROR("Failed to encoder init to drm\n"); + return ret; + } + + dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev); + + ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, + DRM_BRIDGE_ATTACH_NO_CONNECTOR); + if (ret) + goto err_cleanup_encoder; + + dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder); + if (IS_ERR(dsi->connector)) { + DRM_ERROR("Unable to create bridge connector\n"); + ret = PTR_ERR(dsi->connector); + goto err_cleanup_encoder; + } + drm_connector_attach_encoder(dsi->connector, &dsi->encoder); + + return 0; + +err_cleanup_encoder: + drm_encoder_cleanup(&dsi->encoder); + return ret; +} + +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data) +{ + int ret; + struct drm_device *drm = data; + struct mtk_dsi *dsi = dev_get_drvdata(dev); + + ret = mtk_dsi_encoder_init(drm, dsi); + if (ret) + return ret; + + return device_reset_optional(dev); +} + +static void mtk_dsi_unbind(struct device *dev, struct device *master, + void *data) +{ + struct mtk_dsi *dsi = dev_get_drvdata(dev); + + drm_encoder_cleanup(&dsi->encoder); +} + +static const struct component_ops mtk_dsi_component_ops = { + .bind = mtk_dsi_bind, + .unbind = mtk_dsi_unbind, +}; + static int mtk_dsi_host_attach(struct mipi_dsi_host *host, struct mipi_dsi_device *device) { struct mtk_dsi *dsi = host_to_dsi(host); + struct device *dev = host->dev; + int ret;
dsi->lanes = device->lanes; dsi->format = device->format; dsi->mode_flags = device->mode_flags; + dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0); + if (IS_ERR(dsi->next_bridge)) + return PTR_ERR(dsi->next_bridge); + + drm_bridge_add(&dsi->bridge); + + ret = component_add(host->dev, &mtk_dsi_component_ops); + if (ret) { + DRM_ERROR("failed to add dsi_host component: %d\n", ret); + drm_bridge_remove(&dsi->bridge); + return ret; + }
return 0; }
+static int mtk_dsi_host_detach(struct mipi_dsi_host *host, + struct mipi_dsi_device *device) +{ + struct mtk_dsi *dsi = host_to_dsi(host); + + component_del(host->dev, &mtk_dsi_component_ops); + drm_bridge_remove(&dsi->bridge); + return 0; +} + static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi) { int ret; @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
static const struct mipi_dsi_host_ops mtk_dsi_ops = { .attach = mtk_dsi_host_attach, + .detach = mtk_dsi_host_detach, .transfer = mtk_dsi_host_transfer, };
-static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi) -{ - int ret; - - ret = drm_simple_encoder_init(drm, &dsi->encoder, - DRM_MODE_ENCODER_DSI); - if (ret) { - DRM_ERROR("Failed to encoder init to drm\n"); - return ret; - } - - dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev); - - ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, - DRM_BRIDGE_ATTACH_NO_CONNECTOR); - if (ret) - goto err_cleanup_encoder; - - dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder); - if (IS_ERR(dsi->connector)) { - DRM_ERROR("Unable to create bridge connector\n"); - ret = PTR_ERR(dsi->connector); - goto err_cleanup_encoder; - } - drm_connector_attach_encoder(dsi->connector, &dsi->encoder); - - return 0; - -err_cleanup_encoder: - drm_encoder_cleanup(&dsi->encoder); - return ret; -} - -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data) -{ - int ret; - struct drm_device *drm = data; - struct mtk_dsi *dsi = dev_get_drvdata(dev); - - ret = mtk_dsi_encoder_init(drm, dsi); - if (ret) - return ret; - - return device_reset_optional(dev); -} - -static void mtk_dsi_unbind(struct device *dev, struct device *master, - void *data) -{ - struct mtk_dsi *dsi = dev_get_drvdata(dev); - - drm_encoder_cleanup(&dsi->encoder); -} - -static const struct component_ops mtk_dsi_component_ops = { - .bind = mtk_dsi_bind, - .unbind = mtk_dsi_unbind, -}; - static int mtk_dsi_probe(struct platform_device *pdev) { struct mtk_dsi *dsi; struct device *dev = &pdev->dev; - struct drm_panel *panel; struct resource *regs; int irq_num; int ret; @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev) return ret; }
- ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, - &panel, &dsi->next_bridge); - if (ret) - goto err_unregister_host; - - if (panel) { - dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel); - if (IS_ERR(dsi->next_bridge)) { - ret = PTR_ERR(dsi->next_bridge); - goto err_unregister_host; - } - } - dsi->driver_data = of_device_get_match_data(dev);
dsi->engine_clk = devm_clk_get(dev, "engine"); @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev) dsi->bridge.of_node = dev->of_node; dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
- drm_bridge_add(&dsi->bridge); - - ret = component_add(&pdev->dev, &mtk_dsi_component_ops); - if (ret) { - dev_err(&pdev->dev, "failed to add component: %d\n", ret); - goto err_unregister_host; - } - return 0;
err_unregister_host: @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev) struct mtk_dsi *dsi = platform_get_drvdata(pdev);
mtk_output_dsi_disable(dsi); - drm_bridge_remove(&dsi->bridge); - component_del(&pdev->dev, &mtk_dsi_component_ops); mipi_dsi_host_unregister(&dsi->host);
return 0;