[Intel-gfx] [PATCH] drm/i915/dg2: Catch and log more unexpected values in DG1_MSTR_TILE_INTR

[Matt Roper]

On Tue, May 24, 2022 at 10:43:39AM +0100, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Catch and log any garbage in the register, including no tiles marked, or
> multiple tiles marked.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Matt Roper <matthew.d.roper at intel.com>
> ---
> We caught garbage in DG1_MSTR_TILE_INTR with DG2 (actual value 0xF9D2C008)
> during glmark and more badness. So I thought lets log all possible failure
> modes from here and also use per device logging.
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 33 ++++++++++++++++++++++-----------
>  drivers/gpu/drm/i915/i915_reg.h |  1 +
>  2 files changed, 23 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 73cebc6aa650..79853d3fc1ed 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2778,24 +2778,30 @@ static irqreturn_t dg1_irq_handler(int irq, void *arg)
>  	u32 gu_misc_iir;
>  
>  	if (!intel_irqs_enabled(i915))
> -		return IRQ_NONE;
> +		goto none;
>  
>  	master_tile_ctl = dg1_master_intr_disable(regs);
> -	if (!master_tile_ctl) {
> -		dg1_master_intr_enable(regs);
> -		return IRQ_NONE;
> +	if (!master_tile_ctl)
> +		goto enable_none;
> +
> +	if (master_tile_ctl & ~(DG1_MSTR_IRQ | DG1_MSTR_TILE_MASK)) {
> +		drm_warn(&i915->drm, "Garbage in master_tile_ctl: 0x%08x!\n",
> +			 master_tile_ctl);

I know we have a bunch of them already, but shouldn't we be avoiding
printk-based stuff like this inside interrupt handlers?  Should we be
migrating all these error messages over to trace_printk or something
similar that's safer to use?


Matt

> +		goto enable_none;
>  	}
>  
>  	/* FIXME: we only support tile 0 for now. */
> -	if (master_tile_ctl & DG1_MSTR_TILE(0)) {
> -		master_ctl = raw_reg_read(regs, GEN11_GFX_MSTR_IRQ);
> -		raw_reg_write(regs, GEN11_GFX_MSTR_IRQ, master_ctl);
> -	} else {
> -		DRM_ERROR("Tile not supported: 0x%08x\n", master_tile_ctl);
> -		dg1_master_intr_enable(regs);
> -		return IRQ_NONE;
> +	if (REG_FIELD_GET(DG1_MSTR_TILE_MASK, master_tile_ctl) !=
> +	    DG1_MSTR_TILE(0)) {
> +		drm_warn(&i915->drm, "Unexpected irq from tile %u!\n",
> +			 ilog2(REG_FIELD_GET(DG1_MSTR_TILE_MASK,
> +					     master_tile_ctl)));
> +		goto enable_none;
>  	}
>  
> +	master_ctl = raw_reg_read(regs, GEN11_GFX_MSTR_IRQ);
> +	raw_reg_write(regs, GEN11_GFX_MSTR_IRQ, master_ctl);
> +
>  	gen11_gt_irq_handler(gt, master_ctl);
>  
>  	if (master_ctl & GEN11_DISPLAY_IRQ)
> @@ -2810,6 +2816,11 @@ static irqreturn_t dg1_irq_handler(int irq, void *arg)
>  	pmu_irq_stats(i915, IRQ_HANDLED);
>  
>  	return IRQ_HANDLED;
> +
> +enable_none:
> +	dg1_master_intr_enable(regs);
> +none:
> +	return IRQ_NONE;
>  }
>  
>  /* Called from drm generic code, passed 'crtc' which
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index d8579ab9384c..eefa301c6430 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5774,6 +5774,7 @@
>  
>  #define DG1_MSTR_TILE_INTR		_MMIO(0x190008)
>  #define   DG1_MSTR_IRQ			REG_BIT(31)
> +#define   DG1_MSTR_TILE_MASK		REG_GENMASK(3, 0)
>  #define   DG1_MSTR_TILE(t)		REG_BIT(t)
>  
>  #define GEN11_DISPLAY_INT_CTL		_MMIO(0x44200)
> -- 
> 2.32.0
> 

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation