MEDIA_STATE_VFE only accepts the 'maximum number of threads' in the
range [0, n-1] where n is #EU * (#threads/EU) with the number of threads
based on plaform and the number of EU based on the number of slices and
subslices. This is a fixed number per platform/gt, so appropriately
limit the number of threads we spawn to match the device.

v2: Oversaturate the system with tasks to force execution on every HW
thread; if the thread idles it is returned to the pool and may be reused
again before an unused thread.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2024
Fixes: 47f8253d2b89 ("drm/i915/gen7: Clear all EU/L3 residual contexts")
Signed-off-by: Chris Wilson <[email protected]>
Cc: Mika Kuoppala <[email protected]>
Cc: Prathap Kumar Valsan <[email protected]>
Cc: Akeem G Abodunrin <[email protected]>
Cc: Jon Bloomfield <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Randy Wright <[email protected]>
Cc: [email protected] # v5.7+
---
 drivers/gpu/drm/i915/gt/gen7_renderclear.c | 91 ++++++++++++----------
 1 file changed, 49 insertions(+), 42 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/gen7_renderclear.c 
b/drivers/gpu/drm/i915/gt/gen7_renderclear.c
index d93d85cd3027..3ea7c9cc0f3d 100644
--- a/drivers/gpu/drm/i915/gt/gen7_renderclear.c
+++ b/drivers/gpu/drm/i915/gt/gen7_renderclear.c
@@ -7,8 +7,6 @@
 #include "i915_drv.h"
 #include "intel_gpu_commands.h"
 
-#define MAX_URB_ENTRIES 64
-#define STATE_SIZE (4 * 1024)
 #define GT3_INLINE_DATA_DELAYS 0x1E00
 #define batch_advance(Y, CS) GEM_BUG_ON((Y)->end != (CS))
 
@@ -34,38 +32,57 @@ struct batch_chunk {
 };
 
 struct batch_vals {
-       u32 max_primitives;
-       u32 max_urb_entries;
-       u32 cmd_size;
-       u32 state_size;
+       u32 max_threads;
        u32 state_start;
-       u32 batch_size;
+       u32 surface_start;
        u32 surface_height;
        u32 surface_width;
-       u32 scratch_size;
-       u32 max_size;
+       u32 size;
 };
 
+static inline int num_primitives(const struct batch_vals *bv)
+{
+       /*
+        * We need to oversaturate the GPU with work in order to dispatch
+        * a shader on every HW thread.
+        */
+       return bv->max_threads + 2;
+}
+
 static void
 batch_get_defaults(struct drm_i915_private *i915, struct batch_vals *bv)
 {
        if (IS_HASWELL(i915)) {
-               bv->max_primitives = 280;
-               bv->max_urb_entries = MAX_URB_ENTRIES;
+               switch (INTEL_INFO(i915)->gt) {
+               default:
+               case 1:
+                       bv->max_threads = 70;
+                       break;
+               case 2:
+                       bv->max_threads = 140;
+                       break;
+               case 3:
+                       bv->max_threads = 280;
+                       break;
+               }
                bv->surface_height = 16 * 16;
                bv->surface_width = 32 * 2 * 16;
        } else {
-               bv->max_primitives = 128;
-               bv->max_urb_entries = MAX_URB_ENTRIES / 2;
+               switch (INTEL_INFO(i915)->gt) {
+               default:
+               case 1: /* including vlv */
+                       bv->max_threads = 36;
+                       break;
+               case 2:
+                       bv->max_threads = 128;
+                       break;
+               }
                bv->surface_height = 16 * 8;
                bv->surface_width = 32 * 16;
        }
-       bv->cmd_size = bv->max_primitives * 4096;
-       bv->state_size = STATE_SIZE;
-       bv->state_start = bv->cmd_size;
-       bv->batch_size = bv->cmd_size + bv->state_size;
-       bv->scratch_size = bv->surface_height * bv->surface_width;
-       bv->max_size = bv->batch_size + bv->scratch_size;
+       bv->state_start = round_up(SZ_1K + num_primitives(bv) * 64, SZ_4K);
+       bv->surface_start = bv->state_start + SZ_4K;
+       bv->size = bv->surface_start + bv->surface_height * bv->surface_width;
 }
 
 static void batch_init(struct batch_chunk *bc,
@@ -155,7 +172,8 @@ static u32
 gen7_fill_binding_table(struct batch_chunk *state,
                        const struct batch_vals *bv)
 {
-       u32 surface_start = gen7_fill_surface_state(state, bv->batch_size, bv);
+       u32 surface_start =
+               gen7_fill_surface_state(state, bv->surface_start, bv);
        u32 *cs = batch_alloc_items(state, 32, 8);
        u32 offset = batch_offset(state, cs);
 
@@ -244,8 +262,7 @@ gen7_emit_vfe_state(struct batch_chunk *batch,
                    u32 urb_size, u32 curbe_size,
                    u32 mode)
 {
-       u32 urb_entries = bv->max_urb_entries;
-       u32 threads = bv->max_primitives - 1;
+       u32 threads = bv->max_threads - 1;
        u32 *cs = batch_alloc_items(batch, 32, 8);
 
        *cs++ = MEDIA_VFE_STATE | (8 - 2);
@@ -254,7 +271,7 @@ gen7_emit_vfe_state(struct batch_chunk *batch,
        *cs++ = 0;
 
        /* number of threads & urb entries for GPGPU vs Media Mode */
-       *cs++ = threads << 16 | urb_entries << 8 | mode << 2;
+       *cs++ = threads << 16 | 1 << 8 | mode << 2;
 
        *cs++ = 0;
 
@@ -293,17 +310,12 @@ gen7_emit_media_object(struct batch_chunk *batch,
 {
        unsigned int x_offset = (media_object_index % 16) * 64;
        unsigned int y_offset = (media_object_index / 16) * 16;
-       unsigned int inline_data_size;
-       unsigned int media_batch_size;
-       unsigned int i;
+       unsigned int pkt = 6 + 3;
        u32 *cs;
 
-       inline_data_size = 112 * 8;
-       media_batch_size = inline_data_size + 6;
+       cs = batch_alloc_items(batch, 8, pkt);
 
-       cs = batch_alloc_items(batch, 8, media_batch_size);
-
-       *cs++ = MEDIA_OBJECT | (media_batch_size - 2);
+       *cs++ = MEDIA_OBJECT | (pkt - 2);
 
        /* interface descriptor offset */
        *cs++ = 0;
@@ -320,8 +332,6 @@ gen7_emit_media_object(struct batch_chunk *batch,
        *cs++ = (y_offset << 16) | (x_offset);
        *cs++ = 0;
        *cs++ = GT3_INLINE_DATA_DELAYS;
-       for (i = 3; i < inline_data_size; i++)
-               *cs++ = 0;
 
        batch_advance(batch, cs);
 }
@@ -350,8 +360,8 @@ static void emit_batch(struct i915_vma * const vma,
        u32 interface_descriptor;
        unsigned int i;
 
-       batch_init(&cmds, vma, start, 0, bv->cmd_size);
-       batch_init(&state, vma, start, bv->state_start, bv->state_size);
+       batch_init(&cmds, vma, start, 0, bv->state_start);
+       batch_init(&state, vma, start, bv->state_start, SZ_4K);
 
        interface_descriptor =
                gen7_fill_interface_descriptor(&state, bv,
@@ -359,19 +369,16 @@ static void emit_batch(struct i915_vma * const vma,
                                               &cb_kernel_hsw :
                                               &cb_kernel_ivb,
                                               desc_count);
-       gen7_emit_pipeline_flush(&cmds);
        batch_add(&cmds, PIPELINE_SELECT | PIPELINE_SELECT_MEDIA);
-       batch_add(&cmds, MI_NOOP);
        gen7_emit_state_base_address(&cmds, interface_descriptor);
        gen7_emit_pipeline_flush(&cmds);
 
        gen7_emit_vfe_state(&cmds, bv, urb_size - 1, 0, 0);
-
        gen7_emit_interface_descriptor_load(&cmds,
                                            interface_descriptor,
                                            desc_count);
 
-       for (i = 0; i < bv->max_primitives; i++)
+       for (i = 0; i < num_primitives(bv); i++)
                gen7_emit_media_object(&cmds, i);
 
        batch_add(&cmds, MI_BATCH_BUFFER_END);
@@ -385,15 +392,15 @@ int gen7_setup_clear_gpr_bb(struct intel_engine_cs * 
const engine,
 
        batch_get_defaults(engine->i915, &bv);
        if (!vma)
-               return bv.max_size;
+               return bv.size;
 
-       GEM_BUG_ON(vma->obj->base.size < bv.max_size);
+       GEM_BUG_ON(vma->obj->base.size < bv.size);
 
        batch = i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
        if (IS_ERR(batch))
                return PTR_ERR(batch);
 
-       emit_batch(vma, memset(batch, 0, bv.max_size), &bv);
+       emit_batch(vma, memset(batch, 0, bv.size), &bv);
 
        i915_gem_object_flush_map(vma->obj);
        __i915_gem_object_release_map(vma->obj);
-- 
2.20.1

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