drm/i915: Apply missed interrupt after reset w/a to all ringbuffer gen

Having completed a test run of gem_eio across all machines in CI we also
observe the phenomenon (of lost interrupts after resetting the GPU) on
gen3 machines as well as the previously sighted gen6/gen7. Let's apply
the same HWSTAM workaround that was effective for gen6+ for all, as
although we haven't seen the same failure on gen4/5 it seems prudent to
keep the code the same.

As a consequence we can remove the extra setting of HWSTAM and apply the
register from a single site.

v2: Delazy and move the HWSTAM into its own function
v3: Mask off all HWSP writes on driver unload and engine cleanup.
v4: And what about the physical hwsp?
v5: No, engine->init_hw() is not called from driver_init_hw(), don't be
daft. Really scrub HWSTAM as early as we can in driver_init_mmio()
v6: Rename set_hwsp as it was setting the mask not the hwsp register.
v7: Ville pointed out that although vcs(bsd) was introduced for g4x/ilk,
per-engine HWSTAM was not introduced until gen6!

References: https://bugs.freedesktop.org/show_bug.cgi?id=108735
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181218102712.11058-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e2dac9b..0c7fc98 100644 (file)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3586,9 +3586,6 @@ static void ironlake_irq_reset(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = to_i915(dev);
 
-       if (IS_GEN(dev_priv, 5))
-               I915_WRITE(HWSTAM, 0xffffffff);
-
        GEN3_IRQ_RESET(DE);
        if (IS_GEN(dev_priv, 7))
                I915_WRITE(GEN7_ERR_INT, 0xffffffff);
@@ -4368,8 +4365,6 @@ static void i8xx_irq_reset(struct drm_device *dev)
 
        i9xx_pipestat_irq_reset(dev_priv);
 
-       I915_WRITE16(HWSTAM, 0xffff);
-
        GEN2_IRQ_RESET();
 }
 
@@ -4537,8 +4532,6 @@ static void i915_irq_reset(struct drm_device *dev)
 
        i9xx_pipestat_irq_reset(dev_priv);
 
-       I915_WRITE(HWSTAM, 0xffffffff);
-
        GEN3_IRQ_RESET();
 }
 
@@ -4648,8 +4641,6 @@ static void i965_irq_reset(struct drm_device *dev)
 
        i9xx_pipestat_irq_reset(dev_priv);
 
-       I915_WRITE(HWSTAM, 0xffffffff);
-
        GEN3_IRQ_RESET();
 }
 

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 66d0ad9..561b474 100644 (file)
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -261,6 +261,31 @@ static void __sprint_engine_name(char *name, const struct engine_info *info)
                         info->instance) >= INTEL_ENGINE_CS_MAX_NAME);
 }
 
+void intel_engine_set_hwsp_writemask(struct intel_engine_cs *engine, u32 mask)
+{
+       struct drm_i915_private *dev_priv = engine->i915;
+       i915_reg_t hwstam;
+
+       /*
+        * Though they added more rings on g4x/ilk, they did not add
+        * per-engine HWSTAM until gen6.
+        */
+       if (INTEL_GEN(dev_priv) < 6 && engine->class != RENDER_CLASS)
+               return;
+
+       hwstam = RING_HWSTAM(engine->mmio_base);
+       if (INTEL_GEN(dev_priv) >= 3)
+               I915_WRITE(hwstam, mask);
+       else
+               I915_WRITE16(hwstam, mask);
+}
+
+static void intel_engine_sanitize_mmio(struct intel_engine_cs *engine)
+{
+       /* Mask off all writes into the unknown HWSP */
+       intel_engine_set_hwsp_writemask(engine, ~0u);
+}
+
 static int
 intel_engine_setup(struct drm_i915_private *dev_priv,
                   enum intel_engine_id id)
@@ -312,6 +337,9 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
 
        ATOMIC_INIT_NOTIFIER_HEAD(&engine->context_status_notifier);
 
+       /* Scrub mmio state on takeover */
+       intel_engine_sanitize_mmio(engine);
+
        dev_priv->engine_class[info->class][info->instance] = engine;
        dev_priv->engine[id] = engine;
        return 0;
@@ -495,6 +523,9 @@ void intel_engine_setup_common(struct intel_engine_cs *engine)
 
 static void cleanup_status_page(struct intel_engine_cs *engine)
 {
+       /* Prevent writes into HWSP after returning the page to the system */
+       intel_engine_set_hwsp_writemask(engine, ~0u);
+
        if (HWS_NEEDS_PHYSICAL(engine->i915)) {
                void *addr = fetch_and_zero(&engine->status_page.page_addr);
 

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index f16fb30..4762c1e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1655,7 +1655,7 @@ static void enable_execlists(struct intel_engine_cs *engine)
 {
        struct drm_i915_private *dev_priv = engine->i915;
 
-       I915_WRITE(RING_HWSTAM(engine->mmio_base), 0xffffffff);
+       intel_engine_set_hwsp_writemask(engine, ~0u); /* HWSTAM */
 
        /*
         * Make sure we're not enabling the new 12-deep CSB

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index fdeca2b..65fd92e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -379,11 +379,25 @@ gen7_render_ring_flush(struct i915_request *rq, u32 mode)
        return 0;
 }
 
-static void ring_setup_phys_status_page(struct intel_engine_cs *engine)
+static void set_hwstam(struct intel_engine_cs *engine, u32 mask)
+{
+       /*
+        * Keep the render interrupt unmasked as this papers over
+        * lost interrupts following a reset.
+        */
+       if (engine->class == RENDER_CLASS) {
+               if (INTEL_GEN(engine->i915) >= 6)
+                       mask &= ~BIT(0);
+               else
+                       mask &= ~I915_USER_INTERRUPT;
+       }
+
+       intel_engine_set_hwsp_writemask(engine, mask);
+}
+
+static void set_hws_pga(struct intel_engine_cs *engine, phys_addr_t phys)
 {
        struct drm_i915_private *dev_priv = engine->i915;
-       struct page *page = virt_to_page(engine->status_page.page_addr);
-       phys_addr_t phys = PFN_PHYS(page_to_pfn(page));
        u32 addr;
 
        addr = lower_32_bits(phys);
@@ -393,12 +407,22 @@ static void ring_setup_phys_status_page(struct intel_engine_cs *engine)
        I915_WRITE(HWS_PGA, addr);
 }
 
-static void intel_ring_setup_status_page(struct intel_engine_cs *engine)
+static void ring_setup_phys_status_page(struct intel_engine_cs *engine)
+{
+       struct page *page = virt_to_page(engine->status_page.page_addr);
+       phys_addr_t phys = PFN_PHYS(page_to_pfn(page));
+
+       set_hws_pga(engine, phys);
+       set_hwstam(engine, ~0u);
+}
+
+static void set_hwsp(struct intel_engine_cs *engine, u32 offset)
 {
        struct drm_i915_private *dev_priv = engine->i915;
-       i915_reg_t mmio;
+       i915_reg_t hwsp;
 
-       /* The ring status page addresses are no longer next to the rest of
+       /*
+        * The ring status page addresses are no longer next to the rest of
         * the ring registers as of gen7.
         */
        if (IS_GEN(dev_priv, 7)) {
@@ -410,56 +434,55 @@ static void intel_ring_setup_status_page(struct intel_engine_cs *engine)
                default:
                        GEM_BUG_ON(engine->id);
                case RCS:
-                       mmio = RENDER_HWS_PGA_GEN7;
+                       hwsp = RENDER_HWS_PGA_GEN7;
                        break;
                case BCS:
-                       mmio = BLT_HWS_PGA_GEN7;
+                       hwsp = BLT_HWS_PGA_GEN7;
                        break;
                case VCS:
-                       mmio = BSD_HWS_PGA_GEN7;
+                       hwsp = BSD_HWS_PGA_GEN7;
                        break;
                case VECS:
-                       mmio = VEBOX_HWS_PGA_GEN7;
+                       hwsp = VEBOX_HWS_PGA_GEN7;
                        break;
                }
        } else if (IS_GEN(dev_priv, 6)) {
-               mmio = RING_HWS_PGA_GEN6(engine->mmio_base);
+               hwsp = RING_HWS_PGA_GEN6(engine->mmio_base);
        } else {
-               mmio = RING_HWS_PGA(engine->mmio_base);
+               hwsp = RING_HWS_PGA(engine->mmio_base);
        }
 
-       if (INTEL_GEN(dev_priv) >= 6) {
-               u32 mask = ~0u;
+       I915_WRITE(hwsp, offset);
+       POSTING_READ(hwsp);
+}
 
-               /*
-                * Keep the render interrupt unmasked as this papers over
-                * lost interrupts following a reset.
-                */
-               if (engine->id == RCS)
-                       mask &= ~BIT(0);
+static void flush_cs_tlb(struct intel_engine_cs *engine)
+{
+       struct drm_i915_private *dev_priv = engine->i915;
+       i915_reg_t instpm = RING_INSTPM(engine->mmio_base);
 
-               I915_WRITE(RING_HWSTAM(engine->mmio_base), mask);
-       }
+       if (!IS_GEN_RANGE(dev_priv, 6, 7))
+               return;
 
-       I915_WRITE(mmio, engine->status_page.ggtt_offset);
-       POSTING_READ(mmio);
+       /* ring should be idle before issuing a sync flush*/
+       WARN_ON((I915_READ_MODE(engine) & MODE_IDLE) == 0);
 
-       /* Flush the TLB for this page */
-       if (IS_GEN_RANGE(dev_priv, 6, 7)) {
-               i915_reg_t reg = RING_INSTPM(engine->mmio_base);
+       I915_WRITE(instpm,
+                  _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
+                                     INSTPM_SYNC_FLUSH));
+       if (intel_wait_for_register(dev_priv,
+                                   instpm, INSTPM_SYNC_FLUSH, 0,
+                                   1000))
+               DRM_ERROR("%s: wait for SyncFlush to complete for TLB invalidation timed out\n",
+                         engine->name);
+}
 
-               /* ring should be idle before issuing a sync flush*/
-               WARN_ON((I915_READ_MODE(engine) & MODE_IDLE) == 0);
+static void ring_setup_status_page(struct intel_engine_cs *engine)
+{
+       set_hwsp(engine, engine->status_page.ggtt_offset);
+       set_hwstam(engine, ~0u);
 
-               I915_WRITE(reg,
-                          _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
-                                             INSTPM_SYNC_FLUSH));
-               if (intel_wait_for_register(dev_priv,
-                                           reg, INSTPM_SYNC_FLUSH, 0,
-                                           1000))
-                       DRM_ERROR("%s: wait for SyncFlush to complete for TLB invalidation timed out\n",
-                                 engine->name);
-       }
+       flush_cs_tlb(engine);
 }
 
 static bool stop_ring(struct intel_engine_cs *engine)
@@ -529,7 +552,7 @@ static int init_ring_common(struct intel_engine_cs *engine)
        if (HWS_NEEDS_PHYSICAL(dev_priv))
                ring_setup_phys_status_page(engine);
        else
-               intel_ring_setup_status_page(engine);
+               ring_setup_status_page(engine);
 
        intel_engine_reset_breadcrumbs(engine);
 

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 1ae74e5..6b41b9c 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -903,6 +903,8 @@ int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine);
 int intel_engine_stop_cs(struct intel_engine_cs *engine);
 void intel_engine_cancel_stop_cs(struct intel_engine_cs *engine);
 
+void intel_engine_set_hwsp_writemask(struct intel_engine_cs *engine, u32 mask);
+
 u64 intel_engine_get_active_head(const struct intel_engine_cs *engine);
 u64 intel_engine_get_last_batch_head(const struct intel_engine_cs *engine);