Hi, Angelo:
On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
Hi, Angelo:
On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
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
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); }
[snip]
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);
The original would process panel. Why do you remove the panel part? It's better that someone has a platform of DSI->Panel to test this patch.
Sorry, devm_drm_of_get_bridge() has processed the panel part, so for this patch,
Reviewed-by: CK Hu ck.hu@mediatek.com
Regards, CK
- 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,
};
[snip]
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;