[Intel-gfx] [PATCH] drm/i915/guc/slpc: Check GuC status before freq boost

[Vinay Belgaumkar]

It's possible that i915 might get wedged between a boost
and un-boost. Validate the i915-GuC connection before trying
to send a H2G to change the min frequency.

Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/4464

Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
index 4e1d3cd29164..22c1c12369f2 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
@@ -183,11 +183,15 @@ static int slpc_unset_param(struct intel_guc_slpc *slpc,
 static int slpc_force_min_freq(struct intel_guc_slpc *slpc, u32 freq)
 {
 	struct drm_i915_private *i915 = slpc_to_i915(slpc);
+	struct intel_guc *guc = slpc_to_guc(slpc);
 	intel_wakeref_t wakeref;
 	int ret = 0;
 
 	lockdep_assert_held(&slpc->lock);
 
+	if (!intel_guc_is_ready(guc))
+		return -ENODEV;
+
 	/*
 	 * This function is a little different as compared to
 	 * intel_guc_slpc_set_min_freq(). Softlimit will not be updated
-- 
2.25.0