diff options
| -rw-r--r-- | drivers/gpu/drm/i915/gt/intel_workarounds.c | 39 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_reg.h | 1 |
2 files changed, 38 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c index e9b8af9f08ea..688ed04edbf6 100644 --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c @@ -644,6 +644,37 @@ static void dg1_ctx_workarounds_init(struct intel_engine_cs *engine, DG1_HZ_READ_SUPPRESSION_OPTIMIZATION_DISABLE); } +static void fakewa_disable_nestedbb_mode(struct intel_engine_cs *engine, + struct i915_wa_list *wal) +{ + /* + * This is a "fake" workaround defined by software to ensure we + * maintain reliable, backward-compatible behavior for userspace with + * regards to how nested MI_BATCH_BUFFER_START commands are handled. + * + * The per-context setting of MI_MODE[12] determines whether the bits + * of a nested MI_BATCH_BUFFER_START instruction should be interpreted + * in the traditional manner or whether they should instead use a new + * tgl+ meaning that breaks backward compatibility, but allows nesting + * into 3rd-level batchbuffers. When this new capability was first + * added in TGL, it remained off by default unless a context + * intentionally opted in to the new behavior. However Xe_HPG now + * flips this on by default and requires that we explicitly opt out if + * we don't want the new behavior. + * + * From a SW perspective, we want to maintain the backward-compatible + * behavior for userspace, so we'll apply a fake workaround to set it + * back to the legacy behavior on platforms where the hardware default + * is to break compatibility. At the moment there is no Linux + * userspace that utilizes third-level batchbuffers, so this will avoid + * userspace from needing to make any changes. using the legacy + * meaning is the correct thing to do. If/when we have userspace + * consumers that want to utilize third-level batch nesting, we can + * provide a context parameter to allow them to opt-in. + */ + wa_masked_dis(wal, RING_MI_MODE(engine->mmio_base), TGL_NESTED_BB_EN); +} + static void __intel_engine_init_ctx_wa(struct intel_engine_cs *engine, struct i915_wa_list *wal, @@ -651,11 +682,15 @@ __intel_engine_init_ctx_wa(struct intel_engine_cs *engine, { struct drm_i915_private *i915 = engine->i915; + wa_init_start(wal, name, engine->name); + + /* Applies to all engines */ + if (GRAPHICS_VER_FULL(i915) >= IP_VER(12, 55)) + fakewa_disable_nestedbb_mode(engine, wal); + if (engine->class != RENDER_CLASS) return; - wa_init_start(wal, name, engine->name); - if (IS_DG1(i915)) dg1_ctx_workarounds_init(engine, wal); else if (GRAPHICS_VER(i915) == 12) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index f79f02ee12db..b289f5cefa59 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -2830,6 +2830,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg) #define MI_MODE _MMIO(0x209c) # define VS_TIMER_DISPATCH (1 << 6) # define MI_FLUSH_ENABLE (1 << 12) +# define TGL_NESTED_BB_EN (1 << 12) # define ASYNC_FLIP_PERF_DISABLE (1 << 14) # define MODE_IDLE (1 << 9) # define STOP_RING (1 << 8) |