Re: [PATCH] drm/msm/dsi: do not install irq handler before power up the host

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On 21/09/2021 21:26, Andrzej Hajda wrote:
W dniu 21.09.2021 o 18:22, Dmitry Baryshkov pisze:
The DSI host might be left in some state by the bootloader. If this
state generates an IRQ, it might hang the system by holding the
interrupt line before the driver sets up the DSI host to the known
state.

Move the request/free_irq calls into msm_dsi_host_power_on/_off calls,
so that we can be sure that the interrupt is delivered when the host is
in the known state.


The established practice is to request IRQ in probe, to avoid
auto-enabling use IRQF_NO_AUTOEN flag.

Then you can call enable_irq in power-on.

Nice idea, thank you! I somehow missed addition of IRQF_NO_AUTOEN. I've used it in v2 ([PATCH v2] drm/msm/dsi: do not enable irq handler before powering up the host).



Regards

Andrzej




Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
---
   drivers/gpu/drm/msm/dsi/dsi_host.c | 21 ++++++++++++---------
   1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index e269df285136..cd842347a6b1 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1951,15 +1951,6 @@ int msm_dsi_host_modeset_init(struct mipi_dsi_host *host,
   		return ret;
   	}
- ret = devm_request_irq(&pdev->dev, msm_host->irq,
-			dsi_host_irq, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
-			"dsi_isr", msm_host);
-	if (ret < 0) {
-		DRM_DEV_ERROR(&pdev->dev, "failed to request IRQ%u: %d\n",
-				msm_host->irq, ret);
-		return ret;
-	}
-
   	msm_host->dev = dev;
   	ret = cfg_hnd->ops->tx_buf_alloc(msm_host, SZ_4K);
   	if (ret) {
@@ -2413,6 +2404,16 @@ int msm_dsi_host_power_on(struct mipi_dsi_host *host,
   	if (msm_host->disp_en_gpio)
   		gpiod_set_value(msm_host->disp_en_gpio, 1);
+ ret = devm_request_irq(&msm_host->pdev->dev, msm_host->irq,
+			dsi_host_irq, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+			"dsi_isr", msm_host);
+	if (ret < 0) {
+		DRM_DEV_ERROR(&msm_host->pdev->dev, "failed to request IRQ%u: %d\n",
+				msm_host->irq, ret);
+		return ret;
+	}
+
+
   	msm_host->power_on = true;
   	mutex_unlock(&msm_host->dev_mutex);
@@ -2439,6 +2440,8 @@ int msm_dsi_host_power_off(struct mipi_dsi_host *host)
   		goto unlock_ret;
   	}
+ devm_free_irq(&msm_host->pdev->dev, msm_host->irq, msm_host);
+
   	dsi_ctrl_config(msm_host, false, NULL, NULL);
if (msm_host->disp_en_gpio)


--
With best wishes
Dmitry



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