From: Stuart Summers <stuart.summers@xxxxxxxxx>
The driver is set currently to fail modprobe when GuC is disabled
(enable_guc=0) after GuC has been loaded on a previous modprobe.
For GuC deprivilege, the BIOS is setting the locked bit, so the
driver always considers the GuC to have been loaded and thus does
not support enable_guc=0 on these platforms.
There are some debug scenarios where loading without GuC can be
interesting. Add a new feature flag for GuC deprivilege and a mode
(enable_guc=0x80) which can be exclusively set to skip the locked
bit check.
cc: Radhakrishna Sripada <radhakrishna.sripada@xxxxxxxxx>
Signed-off-by: Stuart Summers <stuart.summers@xxxxxxxxx>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/uc/intel_uc.c | 17 +++++++++++++++--
drivers/gpu/drm/i915/i915_params.h | 1 +
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
index da199aa6989f..a1376dbd04fe 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
@@ -108,7 +108,7 @@ static void __confirm_options(struct intel_uc *uc)
"Incompatible option enable_guc=%d - %s\n",
i915->params.enable_guc, "GuC submission is N/A");
- if (i915->params.enable_guc & ~ENABLE_GUC_MASK)
+ if (i915->params.enable_guc & ~(ENABLE_GUC_MASK | ENABLE_GUC_DO_NOT_LOAD_GUC))
drm_info(&i915->drm,
"Incompatible option enable_guc=%d - %s\n",
i915->params.enable_guc, "undocumented flag");
@@ -416,8 +416,21 @@ static bool uc_is_wopcm_locked(struct intel_uc *uc)
(intel_uncore_read(uncore, DMA_GUC_WOPCM_OFFSET) & GUC_WOPCM_OFFSET_VALID);
}
+static inline bool skip_lock_check(struct drm_i915_private *i915)
+{
+ /*
+ * For platforms with GuC deprivilege, if a user *really* wants
+ * to run without GuC, let that happen by setting enable_guc=0x80.
+ */
+ return (HAS_GUC_DEPRIVILEGE(i915) &&
+ (i915->params.enable_guc & ENABLE_GUC_DO_NOT_LOAD_GUC) &&
+ !(i915->params.enable_guc & ~ENABLE_GUC_DO_NOT_LOAD_GUC));
+}
+
static int __uc_check_hw(struct intel_uc *uc)
{
+ struct drm_i915_private *i915 = uc_to_gt(uc)->i915;
+
if (!intel_uc_supports_guc(uc))
return 0;
@@ -426,7 +439,7 @@ static int __uc_check_hw(struct intel_uc *uc)
* before on this system after reboot, otherwise we risk GPU hangs.
* To check if GuC was loaded before we look at WOPCM registers.
*/
- if (uc_is_wopcm_locked(uc))
+ if (uc_is_wopcm_locked(uc) && likely(!skip_lock_check(i915)))
return -EIO;
return 0;
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index c9d53ff910a0..8996ba2cc3a8 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -32,6 +32,7 @@ struct drm_printer;
#define ENABLE_GUC_SUBMISSION BIT(0)
#define ENABLE_GUC_LOAD_HUC BIT(1)
+#define ENABLE_GUC_DO_NOT_LOAD_GUC BIT(7)
#define ENABLE_GUC_MASK GENMASK(1, 0)
/*
--
2.20.1
