[PATCH v2 0/5] drm: Use IRQF_NO_AUTOEN flag in request_irq()

[PATCH v2 0/5] drm: Use IRQF_NO_AUTOEN flag in request_irq()

[Jinjie Ruan]

As commit cbe16f35bee6 ("genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()")
said, reqeust_irq() and then disable_irq() is unsafe. In the small time gap
between request_irq() and disable_irq(), interrupts can still come.

IRQF_NO_AUTOEN flag can be used by drivers to request_irq(). It prevents
the automatic enabling of the requested interrupt in the same
safe way. With that the usage can be simplified and corrected.

Compile-tested only.

Changes in v2:
- Correct the commit subject.
- Add reviewed-by.

Jinjie Ruan (5):
  drm/imx: Use IRQF_NO_AUTOEN flag in request_irq()
  drm/imx/dcss: Use IRQF_NO_AUTOEN flag in request_irq()
  drm/imx/ipuv3: Use IRQF_NO_AUTOEN flag in request_irq()
  drm/tegra: dpaux: Use IRQF_NO_AUTOEN flag in request_irq()
  drm/msm/adreno: Use IRQF_NO_AUTOEN flag in request_irq()

 drivers/gpu/drm/imx/dcss/dcss-crtc.c   | 6 ++----
 drivers/gpu/drm/imx/dcss/dcss-dtg.c    | 4 +---
 drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c | 6 ++----
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c  | 4 +---
 drivers/gpu/drm/tegra/dpaux.c          | 4 +---
 5 files changed, 7 insertions(+), 17 deletions(-)

-- 
2.34.1

[PATCH v2 1/5] drm/imx: Use IRQF_NO_AUTOEN flag in request_irq()

[Jinjie Ruan]

disable_irq() after request_irq() still has a time gap in which
interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
disable IRQ auto-enable when request IRQ.

Fixes: 9021c317b770 ("drm/imx: Add initial support for DCSS on iMX8MQ")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v2:
- Update the commit subject.
---
 drivers/gpu/drm/imx/dcss/dcss-crtc.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/imx/dcss/dcss-crtc.c b/drivers/gpu/drm/imx/dcss/dcss-crtc.c
index 31267c00782f..af91e45b5d13 100644
--- a/drivers/gpu/drm/imx/dcss/dcss-crtc.c
+++ b/drivers/gpu/drm/imx/dcss/dcss-crtc.c
@@ -206,15 +206,13 @@ int dcss_crtc_init(struct dcss_crtc *crtc, struct drm_device *drm)
 	if (crtc->irq < 0)
 		return crtc->irq;
 
-	ret = request_irq(crtc->irq, dcss_crtc_irq_handler,
-			  0, "dcss_drm", crtc);
+	ret = request_irq(crtc->irq, dcss_crtc_irq_handler, IRQF_NO_AUTOEN,
+			  "dcss_drm", crtc);
 	if (ret) {
 		dev_err(dcss->dev, "irq request failed with %d.\n", ret);
 		return ret;
 	}
 
-	disable_irq(crtc->irq);
-
 	return 0;
 }
 
-- 
2.34.1

Re: [PATCH v2 1/5] drm/imx: Use IRQF_NO_AUTOEN flag in request_irq()

[Laurentiu Palcu]

Hi Jinjie,

On Thu, Sep 12, 2024 at 04:30:16PM +0800, Jinjie Ruan wrote:
> disable_irq() after request_irq() still has a time gap in which
> interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
> disable IRQ auto-enable when request IRQ.
> 
> Fixes: 9021c317b770 ("drm/imx: Add initial support for DCSS on iMX8MQ")
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>

I think the commit subject should start with drm/imx/dcss. Not sure if
this is worth another patch set just for that. I suppose the commiter
could fix it before pushing.

Other than that:
Reviewed-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>

Thanks,
Laurentiu

> ---
> v2:
> - Update the commit subject.
> ---
>  drivers/gpu/drm/imx/dcss/dcss-crtc.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/imx/dcss/dcss-crtc.c b/drivers/gpu/drm/imx/dcss/dcss-crtc.c
> index 31267c00782f..af91e45b5d13 100644
> --- a/drivers/gpu/drm/imx/dcss/dcss-crtc.c
> +++ b/drivers/gpu/drm/imx/dcss/dcss-crtc.c
> @@ -206,15 +206,13 @@ int dcss_crtc_init(struct dcss_crtc *crtc, struct drm_device *drm)
>  	if (crtc->irq < 0)
>  		return crtc->irq;
>  
> -	ret = request_irq(crtc->irq, dcss_crtc_irq_handler,
> -			  0, "dcss_drm", crtc);
> +	ret = request_irq(crtc->irq, dcss_crtc_irq_handler, IRQF_NO_AUTOEN,
> +			  "dcss_drm", crtc);
>  	if (ret) {
>  		dev_err(dcss->dev, "irq request failed with %d.\n", ret);
>  		return ret;
>  	}
>  
> -	disable_irq(crtc->irq);
> -
>  	return 0;
>  }
>  
> -- 
> 2.34.1
> 

[PATCH v2 2/5] drm/imx/dcss: Use IRQF_NO_AUTOEN flag in request_irq()

[Jinjie Ruan]

disable_irq() after request_irq() still has a time gap in which
interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
disable IRQ auto-enable when request IRQ.

Fixes: 9021c317b770 ("drm/imx: Add initial support for DCSS on iMX8MQ")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v2:
- Add Reviewed-by.
---
 drivers/gpu/drm/imx/dcss/dcss-dtg.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/imx/dcss/dcss-dtg.c b/drivers/gpu/drm/imx/dcss/dcss-dtg.c
index 2968f5d5bd41..6bbfd9aa27ac 100644
--- a/drivers/gpu/drm/imx/dcss/dcss-dtg.c
+++ b/drivers/gpu/drm/imx/dcss/dcss-dtg.c
@@ -134,14 +134,12 @@ static int dcss_dtg_irq_config(struct dcss_dtg *dtg,
 		    dtg->base_reg + DCSS_DTG_INT_MASK);
 
 	ret = request_irq(dtg->ctxld_kick_irq, dcss_dtg_irq_handler,
-			  0, "dcss_ctxld_kick", dtg);
+			  IRQF_NO_AUTOEN, "dcss_ctxld_kick", dtg);
 	if (ret) {
 		dev_err(dtg->dev, "dtg: irq request failed.\n");
 		return ret;
 	}
 
-	disable_irq(dtg->ctxld_kick_irq);
-
 	dtg->ctxld_kick_irq_en = false;
 
 	return 0;
-- 
2.34.1

Re: [PATCH v2 2/5] drm/imx/dcss: Use IRQF_NO_AUTOEN flag in request_irq()

[Laurentiu Palcu]

On Thu, Sep 12, 2024 at 04:30:17PM +0800, Jinjie Ruan wrote:
> disable_irq() after request_irq() still has a time gap in which
> interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
> disable IRQ auto-enable when request IRQ.
> 
> Fixes: 9021c317b770 ("drm/imx: Add initial support for DCSS on iMX8MQ")
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>

Reviewed-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>

Thanks,
Laurentiu

> ---
> v2:
> - Add Reviewed-by.
> ---
>  drivers/gpu/drm/imx/dcss/dcss-dtg.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/imx/dcss/dcss-dtg.c b/drivers/gpu/drm/imx/dcss/dcss-dtg.c
> index 2968f5d5bd41..6bbfd9aa27ac 100644
> --- a/drivers/gpu/drm/imx/dcss/dcss-dtg.c
> +++ b/drivers/gpu/drm/imx/dcss/dcss-dtg.c
> @@ -134,14 +134,12 @@ static int dcss_dtg_irq_config(struct dcss_dtg *dtg,
>  		    dtg->base_reg + DCSS_DTG_INT_MASK);
>  
>  	ret = request_irq(dtg->ctxld_kick_irq, dcss_dtg_irq_handler,
> -			  0, "dcss_ctxld_kick", dtg);
> +			  IRQF_NO_AUTOEN, "dcss_ctxld_kick", dtg);
>  	if (ret) {
>  		dev_err(dtg->dev, "dtg: irq request failed.\n");
>  		return ret;
>  	}
>  
> -	disable_irq(dtg->ctxld_kick_irq);
> -
>  	dtg->ctxld_kick_irq_en = false;
>  
>  	return 0;
> -- 
> 2.34.1
> 

[PATCH v2 3/5] drm/imx/ipuv3: Use IRQF_NO_AUTOEN flag in request_irq()

[Jinjie Ruan]

disable_irq() after request_irq() still has a time gap in which
interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
disable IRQ auto-enable when request IRQ.

Fixes: 47b1be5c0f4e ("staging: imx/drm: request irq only after adding the crtc")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v2:
- Add Reviewed-by.
---
 drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c
index ef29c9a61a46..99db53e167bd 100644
--- a/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3/ipuv3-crtc.c
@@ -410,14 +410,12 @@ static int ipu_drm_bind(struct device *dev, struct device *master, void *data)
 	}
 
 	ipu_crtc->irq = ipu_plane_irq(ipu_crtc->plane[0]);
-	ret = devm_request_irq(ipu_crtc->dev, ipu_crtc->irq, ipu_irq_handler, 0,
-			"imx_drm", ipu_crtc);
+	ret = devm_request_irq(ipu_crtc->dev, ipu_crtc->irq, ipu_irq_handler,
+			       IRQF_NO_AUTOEN, "imx_drm", ipu_crtc);
 	if (ret < 0) {
 		dev_err(ipu_crtc->dev, "irq request failed with %d.\n", ret);
 		return ret;
 	}
-	/* Only enable IRQ when we actually need it to trigger work. */
-	disable_irq(ipu_crtc->irq);
 
 	return 0;
 }
-- 
2.34.1

Re: [PATCH v2 3/5] drm/imx/ipuv3: Use IRQF_NO_AUTOEN flag in request_irq()

[Philipp Zabel]

On Do, 2024-09-12 at 16:30 +0800, Jinjie Ruan wrote:
> disable_irq() after request_irq() still has a time gap in which
> interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
> disable IRQ auto-enable when request IRQ.
> 
> Fixes: 47b1be5c0f4e ("staging: imx/drm: request irq only after adding the crtc")
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

[PATCH v2 4/5] drm/tegra: dpaux: Use IRQF_NO_AUTOEN flag in request_irq()

[Jinjie Ruan]

disable_irq() after request_irq() still has a time gap in which
interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
disable IRQ auto-enable when request IRQ.

Fixes: 9e532b3ad9a7 ("drm/tegra: dpaux: Disable interrupt when detached")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
 drivers/gpu/drm/tegra/dpaux.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index ae12d001a04b..9646dba950e0 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -517,7 +517,7 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_get_sync(&pdev->dev);
 
-	err = devm_request_irq(dpaux->dev, dpaux->irq, tegra_dpaux_irq, 0,
+	err = devm_request_irq(dpaux->dev, dpaux->irq, tegra_dpaux_irq, IRQF_NO_AUTOEN,
 			       dev_name(dpaux->dev), dpaux);
 	if (err < 0) {
 		dev_err(dpaux->dev, "failed to request IRQ#%u: %d\n",
@@ -525,8 +525,6 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
 		goto err_pm_disable;
 	}
 
-	disable_irq(dpaux->irq);
-
 	dpaux->aux.transfer = tegra_dpaux_transfer;
 	dpaux->aux.dev = &pdev->dev;
 
-- 
2.34.1

[PATCH v2 5/5] drm/msm/adreno: Use IRQF_NO_AUTOEN flag in request_irq()

[Jinjie Ruan]

disable_irq() after request_irq() still has a time gap in which
interrupts can come. request_irq() with IRQF_NO_AUTOEN flag will
disable IRQ auto-enable when request IRQ.

Fixes: 4b565ca5a2cb ("drm/msm: Add A6XX device support")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v2:
- Add Reviewed-by.
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index cb538a262d1c..db36c81d0f12 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -1505,15 +1505,13 @@ static int a6xx_gmu_get_irq(struct a6xx_gmu *gmu, struct platform_device *pdev,
 
 	irq = platform_get_irq_byname(pdev, name);
 
-	ret = request_irq(irq, handler, IRQF_TRIGGER_HIGH, name, gmu);
+	ret = request_irq(irq, handler, IRQF_TRIGGER_HIGH | IRQF_NO_AUTOEN, name, gmu);
 	if (ret) {
 		DRM_DEV_ERROR(&pdev->dev, "Unable to get interrupt %s %d\n",
 			      name, ret);
 		return ret;
 	}
 
-	disable_irq(irq);
-
 	return irq;
 }
 
-- 
2.34.1

Re: (subset) [PATCH v2 0/5] drm: Use IRQF_NO_AUTOEN flag in request_irq()

[Dmitry Baryshkov]

On Thu, 12 Sep 2024 16:30:15 +0800, Jinjie Ruan wrote:
> As commit cbe16f35bee6 ("genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()")
> said, reqeust_irq() and then disable_irq() is unsafe. In the small time gap
> between request_irq() and disable_irq(), interrupts can still come.
> 
> IRQF_NO_AUTOEN flag can be used by drivers to request_irq(). It prevents
> the automatic enabling of the requested interrupt in the same
> safe way. With that the usage can be simplified and corrected.
> 
> [...]

Applied to drm-misc-next, thanks!

[1/5] drm/imx: Use IRQF_NO_AUTOEN flag in request_irq()
      commit: 1af01e14db7e0b45ae502d822776a58c86688763
[2/5] drm/imx/dcss: Use IRQF_NO_AUTOEN flag in request_irq()
      commit: 4380f8624b8bff3637476726351ed7bb8850188a
[3/5] drm/imx/ipuv3: Use IRQF_NO_AUTOEN flag in request_irq()
      commit: 40004709a3d3b07041a473a163ca911ef04ab8bd

Best regards,
-- 
With best wishes
Dmitry