[Intel-gfx] [PATCH] drm/i915/gt: Limit VFE threads based on GT

[Chris Wilson]

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.

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 <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Cc: Prathap Kumar Valsan <prathap.kumar.valsan at intel.com>
Cc: Akeem G Abodunrin <akeem.g.abodunrin at intel.com>
Cc: Balestrieri Francesco <francesco.balestrieri at intel.com>
Cc: Bloomfield Jon <jon.bloomfield at intel.com>
Cc: <stable at vger.kernel.org> # v5.7+
---
 drivers/gpu/drm/i915/gt/gen7_renderclear.c | 35 +++++++++++++++-------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/gen7_renderclear.c b/drivers/gpu/drm/i915/gt/gen7_renderclear.c
index d93d85cd3027..f3b8fea6226e 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))
 
@@ -34,8 +32,7 @@ struct batch_chunk {
 };
 
 struct batch_vals {
-	u32 max_primitives;
-	u32 max_urb_entries;
+	u32 max_primitives; /* == number of VFE threads */
 	u32 cmd_size;
 	u32 state_size;
 	u32 state_start;
@@ -50,18 +47,35 @@ 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_primitives = 70;
+			break;
+		case 2:
+			bv->max_primitives = 140;
+			break;
+		case 3:
+			bv->max_primitives = 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_primitives = 36;
+			break;
+		case 2:
+			bv->max_primitives = 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_size = SZ_4K;
 	bv->state_start = bv->cmd_size;
 	bv->batch_size = bv->cmd_size + bv->state_size;
 	bv->scratch_size = bv->surface_height * bv->surface_width;
@@ -244,7 +258,6 @@ 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 *cs = batch_alloc_items(batch, 32, 8);
 
@@ -254,7 +267,7 @@ 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;
 
-- 
2.20.1