[Intel-gfx] [PATCH] drm/i915/perf: Assert locking for i915_init_oa_perf_state()

[Lionel Landwerlin]

On 30/08/2019 17:40, Chris Wilson wrote:
> We use the context->pin_mutex to serialise updates to the OA config and
> the registers values written into each new context. Document this
> relationship and assert we do hold the context->pin_mutex as used by
> gen8_configure_all_contexts() to serialise updates to the OA config
> itself.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>


Thanks, that's helpful to remember why it works :)

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>


> ---
>   drivers/gpu/drm/i915/i915_perf.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 2c9f46e12622..c1b764233761 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -2305,6 +2305,9 @@ void i915_oa_init_reg_state(struct intel_engine_cs *engine,
>   {
>   	struct i915_perf_stream *stream;
>   
> +	/* perf.exclusive_stream serialised by gen8_configure_all_contexts() */
> +	lockdep_assert_held(&ce->pin_mutex);
> +
>   	if (engine->class != RENDER_CLASS)
>   		return;
>