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

[Jani Nikula]

On Thu, 14 Aug 2025, "Hogander, Jouni" <jouni.hogander at intel.com> wrote:
> 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>

Thanks, pushed to din.

BR,
Jani.

>
>> ---
>>  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;
>>  }
>>  
>

-- 
Jani Nikula, Intel