drm/me/gsc: mei interrupt top half should be in irq disabled context

[PATCH] drm/me/gsc: mei interrupt top half should be in irq disabled context

Posted by Junxiao Chang 1 month, 1 week ago

MEI GSC interrupt comes from i915 or xe driver. It has top half and
bottom half. Top half is called from i915/xe interrupt handler. It
should be in irq disabled context.

With RT kernel(PREEMPT_RT enabled), by default IRQ handler is in
threaded IRQ. MEI GSC top half might be in threaded IRQ context.
generic_handle_irq_safe API could be called from either IRQ or
process context, it disables local IRQ then calls MEI GSC interrupt
top half.

This change fixes B580 GPU boot issue with RT enabled.

Fixes: e02cea83d32d ("drm/xe/gsc: add Battlemage support")
Tested-by: Baoli Zhang <baoli.zhang@intel.com>
Signed-off-by: Junxiao Chang <junxiao.chang@intel.com>
---
 drivers/gpu/drm/xe/xe_heci_gsc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_heci_gsc.c b/drivers/gpu/drm/xe/xe_heci_gsc.c
index a415ca4887914..32d509b113915 100644
--- a/drivers/gpu/drm/xe/xe_heci_gsc.c
+++ b/drivers/gpu/drm/xe/xe_heci_gsc.c
@@ -221,7 +221,7 @@ void xe_heci_gsc_irq_handler(struct xe_device *xe, u32 iir)
 	if (xe->heci_gsc.irq < 0)
 		return;
 
-	ret = generic_handle_irq(xe->heci_gsc.irq);
+	ret = generic_handle_irq_safe(xe->heci_gsc.irq);
 	if (ret)
 		drm_err_ratelimited(&xe->drm, "error handling GSC irq: %d\n", ret);
 }
@@ -241,7 +241,7 @@ void xe_heci_csc_irq_handler(struct xe_device *xe, u32 iir)
 	if (xe->heci_gsc.irq < 0)
 		return;
 
-	ret = generic_handle_irq(xe->heci_gsc.irq);
+	ret = generic_handle_irq_safe(xe->heci_gsc.irq);
 	if (ret)
 		drm_err_ratelimited(&xe->drm, "error handling GSC irq: %d\n", ret);
 }
-- 
2.43.0

Re: [PATCH] drm/me/gsc: mei interrupt top half should be in irq disabled context

Posted by Maarten Lankhorst 1 week, 1 day ago

Thanks for the patch, I pushed it.

I also added Matthew Brost's r-b, as I submitted this patch separately, and b4-am recognised it as the same patch.

Kind regards,
~Maarten Lankhorst

Den 2025-11-07 kl. 04:31, skrev Junxiao Chang:
> MEI GSC interrupt comes from i915 or xe driver. It has top half and
> bottom half. Top half is called from i915/xe interrupt handler. It
> should be in irq disabled context.
> 
> With RT kernel(PREEMPT_RT enabled), by default IRQ handler is in
> threaded IRQ. MEI GSC top half might be in threaded IRQ context.
> generic_handle_irq_safe API could be called from either IRQ or
> process context, it disables local IRQ then calls MEI GSC interrupt
> top half.
> 
> This change fixes B580 GPU boot issue with RT enabled.
> 
> Fixes: e02cea83d32d ("drm/xe/gsc: add Battlemage support")
> Tested-by: Baoli Zhang <baoli.zhang@intel.com>
> Signed-off-by: Junxiao Chang <junxiao.chang@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_heci_gsc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_heci_gsc.c b/drivers/gpu/drm/xe/xe_heci_gsc.c
> index a415ca4887914..32d509b113915 100644
> --- a/drivers/gpu/drm/xe/xe_heci_gsc.c
> +++ b/drivers/gpu/drm/xe/xe_heci_gsc.c
> @@ -221,7 +221,7 @@ void xe_heci_gsc_irq_handler(struct xe_device *xe, u32 iir)
>  	if (xe->heci_gsc.irq < 0)
>  		return;
>  
> -	ret = generic_handle_irq(xe->heci_gsc.irq);
> +	ret = generic_handle_irq_safe(xe->heci_gsc.irq);
>  	if (ret)
>  		drm_err_ratelimited(&xe->drm, "error handling GSC irq: %d\n", ret);
>  }
> @@ -241,7 +241,7 @@ void xe_heci_csc_irq_handler(struct xe_device *xe, u32 iir)
>  	if (xe->heci_gsc.irq < 0)
>  		return;
>  
> -	ret = generic_handle_irq(xe->heci_gsc.irq);
> +	ret = generic_handle_irq_safe(xe->heci_gsc.irq);
>  	if (ret)
>  		drm_err_ratelimited(&xe->drm, "error handling GSC irq: %d\n", ret);
>  }

Re: [PATCH] drm/me/gsc: mei interrupt top half should be in irq disabled context

Posted by Sebastian Andrzej Siewior 1 month, 1 week ago

On 2025-11-07 11:31:52 [+0800], Junxiao Chang wrote:
> MEI GSC interrupt comes from i915 or xe driver. It has top half and
> bottom half. Top half is called from i915/xe interrupt handler. It
> should be in irq disabled context.
> 
> With RT kernel(PREEMPT_RT enabled), by default IRQ handler is in
> threaded IRQ. MEI GSC top half might be in threaded IRQ context.
> generic_handle_irq_safe API could be called from either IRQ or
> process context, it disables local IRQ then calls MEI GSC interrupt
> top half.
> 
> This change fixes B580 GPU boot issue with RT enabled.
> 
> Fixes: e02cea83d32d ("drm/xe/gsc: add Battlemage support")
> Tested-by: Baoli Zhang <baoli.zhang@intel.com>
> Signed-off-by: Junxiao Chang <junxiao.chang@intel.com>

Sounds reasonable.

Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

What about intel_lpe_audio_irq_handler() ?

Sebastian

RE: [PATCH] drm/me/gsc: mei interrupt top half should be in irq disabled context

Posted by Chang, Junxiao 1 month, 1 week ago

>From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>Sent: Thursday, November 6, 2025 3:16 PM
>What about intel_lpe_audio_irq_handler() ?


Good finding. I will try to reproduce the issue which looks like hdmi audio related. If it could be reproduced, a separate patch will be submitted to fix it. Thank you!