From: Stuart Summers stuart.summers@intel.com
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@intel.com Signed-off-by: Stuart Summers stuart.summers@intel.com Signed-off-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Signed-off-by: Ramalingam C ramalingam.c@intel.com --- 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)
/*