[Intel-gfx] [PATCH] drm/i915: Get PM ref before accessing HW register

[Tvrtko Ursulin]

On 08/09/2021 00:27, Vinay Belgaumkar wrote:
> Seeing these errors when GT is likely in suspend state-
> "RPM wakelock ref not held during HW access"
> 
> Ensure GT is awake before trying to access HW registers. Avoid
> reading the register if that is not the case.
> 
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>

Fixes: 41e5c17ebfc2 ("drm/i915/guc/slpc: Sysfs hooks for SLPC")
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko

> ---
>   drivers/gpu/drm/i915/gt/intel_rps.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
> index 3489f5f0cac1..e1a198bbd135 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rps.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rps.c
> @@ -1969,8 +1969,14 @@ u32 intel_rps_read_actual_frequency(struct intel_rps *rps)
>   u32 intel_rps_read_punit_req(struct intel_rps *rps)
>   {
>   	struct intel_uncore *uncore = rps_to_uncore(rps);
> +	struct intel_runtime_pm *rpm = rps_to_uncore(rps)->rpm;
> +	intel_wakeref_t wakeref;
> +	u32 freq = 0;
>   
> -	return intel_uncore_read(uncore, GEN6_RPNSWREQ);
> +	with_intel_runtime_pm_if_in_use(rpm, wakeref)
> +		freq = intel_uncore_read(uncore, GEN6_RPNSWREQ);
> +
> +	return freq;
>   }
>   
>   static u32 intel_rps_get_req(u32 pureq)
>