Hi, Angelo: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> 於 2022年1月31日 週一 下午4:55寫道： > > 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). Applied to mediatek-drm-fixes[1], thanks. [1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes Regards, Chun-Kuang. > > Cc: <stable@xxxxxxxxxxxxxxx> # 5.15.x > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> > Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx> > Reviewed-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> > > --- > drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++-------------- > 1 file changed, 84 insertions(+), 83 deletions(-) > > 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; > -- > 2.33.1 >
