[Intel-gfx] [PATCH 2/2] drm/i915/guc: handle GuC messages received with CTB disabled

[Chris Wilson]

Quoting Daniele Ceraolo Spurio (2019-06-19 22:43:51)
> +/*
> + * Events triggered while CT buffers are disabled are logged in the SCRATCH_15
> + * register using the same bits used in the CT message payload. Since our
> + * communication channel with guc is turned off at this point, we can save the
> + * message and handle it after we turn it back on.
> + */
> +static void guc_clear_mmio_msg(struct intel_guc *guc)
> +{
> +       intel_uncore_write(&guc_to_i915(guc)->uncore, SOFT_SCRATCH(15), 0);

Should the register be cleared on intel_guc_reset()? Otherwise, we would
be associating the stale msg from an earlier guc instance with the
current one.

That would mean clear_mmio_msg would want to be called from
guc_stop_communication not just guc_disable_communication.
-Chris