Re: [Intel-gfx] [PATCH 10/12] drm/i915/guc: Support larger contexts on newer hardware

[Tvrtko Ursulin]

On 13/07/2022 00:31, john.c.harri...@intel.com wrote:
From: Matthew Brost <matthew.br...@intel.com>

The GuC needs a copy of a golden context for implementing watchdog
resets (aka media resets). This context is larger on newer platforms.
So adjust the size being allocated/copied accordingly.

What were the consequences of this being too small? Media watchdog reset 
broken impacting userspace? Platforms? Do we have an IGT testcase? Do we 
need a Fixes: tag? Copy stable?

Regards,

Tvrtko

Signed-off-by: Matthew Brost <matthew.br...@intel.com>
---
  drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c | 10 +++++++---
  1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c 
b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
index ba7541f3ca610..74cbe8eaf5318 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
@@ -464,7 +464,11 @@ static void fill_engine_enable_masks(struct intel_gt *gt,
  }
  
  #define LR_HW_CONTEXT_SIZE (80 * sizeof(u32))
-#define LRC_SKIP_SIZE (LRC_PPHWSP_SZ * PAGE_SIZE + LR_HW_CONTEXT_SIZE)
+#define XEHP_LR_HW_CONTEXT_SIZE (96 * sizeof(u32))
+#define LR_HW_CONTEXT_SZ(i915) (GRAPHICS_VER_FULL(i915) >= IP_VER(12, 50) ? \
+                                   XEHP_LR_HW_CONTEXT_SIZE : \
+                                   LR_HW_CONTEXT_SIZE)
+#define LRC_SKIP_SIZE(i915) (LRC_PPHWSP_SZ * PAGE_SIZE + 
LR_HW_CONTEXT_SZ(i915))
  static int guc_prep_golden_context(struct intel_guc *guc)
  {
        struct intel_gt *gt = guc_to_gt(guc);
@@ -525,7 +529,7 @@ static int guc_prep_golden_context(struct intel_guc *guc)
                 * on all engines).
                 */
                ads_blob_write(guc, ads.eng_state_size[guc_class],
-                              real_size - LRC_SKIP_SIZE);
+                              real_size - LRC_SKIP_SIZE(gt->i915));
                ads_blob_write(guc, ads.golden_context_lrca[guc_class],
                               addr_ggtt);
  
@@ -599,7 +603,7 @@ static void guc_init_golden_context(struct intel_guc *guc)
                }
  
  		GEM_BUG_ON(ads_blob_read(guc, ads.eng_state_size[guc_class]) !=
-                          real_size - LRC_SKIP_SIZE);
+                          real_size - LRC_SKIP_SIZE(gt->i915));
                GEM_BUG_ON(ads_blob_read(guc, 
ads.golden_context_lrca[guc_class]) != addr_ggtt);
  
  		addr_ggtt += alloc_size;