[PATCH] drm/i915: silence rpm wakeref asserts on GEN11_GU_MISC_IIR access

[Hogander, Jouni]

On Tue, 2025-08-05 at 14:56 +0300, Jani Nikula wrote:
> Commit 8d9908e8fe9c ("drm/i915/display: remove small micro-
> optimizations
> in irq handling") not only removed the optimizations, it also enabled
> wakeref asserts for the GEN11_GU_MISC_IIR access. Silence the asserts
> by
> wrapping the access inside
> intel_display_rpm_assert_{block,unblock}().
> 
> Reported-by: Jason A. Donenfeld <Jason at zx2c4.com>
> Closes: https://lore.kernel.org/r/aG0tWkfmxWtxl_xc@zx2c4.com
> Fixes: 8d9908e8fe9c ("drm/i915/display: remove small micro-
> optimizations in irq handling")
> Cc: <stable at vger.kernel.org> # v6.13+
> Suggested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>

Reviewed-by: Jouni Högander <jouni.hogander at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_display_irq.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c
> b/drivers/gpu/drm/i915/display/intel_display_irq.c
> index fb25ec8adae3..68157f177b6a 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_irq.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
> @@ -1506,10 +1506,14 @@ u32 gen11_gu_misc_irq_ack(struct
> intel_display *display, const u32 master_ctl)
>  	if (!(master_ctl & GEN11_GU_MISC_IRQ))
>  		return 0;
>  
> +	intel_display_rpm_assert_block(display);
> +
>  	iir = intel_de_read(display, GEN11_GU_MISC_IIR);
>  	if (likely(iir))
>  		intel_de_write(display, GEN11_GU_MISC_IIR, iir);
>  
> +	intel_display_rpm_assert_unblock(display);
> +
>  	return iir;
>  }
>