From 76c3916887f1225db4b4960c59820db1a995f3cb Mon Sep 17 00:00:00 2001 From: John Harrison Date: Fri, 29 May 2015 17:43:43 +0100 Subject: [PATCH] drm/i915: Update deferred context creation to do explicit request management In execlist mode, context initialisation is deferred until first use of the given context. This is because execlist mode has per ring context state and thus many more context storage objects than legacy mode and many are never actually used. Previously, the initialisation commands were written to the ring and tagged with some random request structure via the OLR. This seemed to be causing a null pointer deference bug under certain circumstances (BZ:88865). This patch adds explicit request creation and submission to the deferred initialisation code path. Thus removing any reliance on or randomness caused by the OLR. Note that it should be possible to move the deferred context creation until even later - when the context is actually switched to rather than when it is merely validated. This would allow the initialisation to be done within the request of the work that is wanting to use the context. Hence, the extra request that is created, used and retired just for the context init could be removed completely. However, this is left for a follow up patch. For: VIZ-5115 Signed-off-by: John Harrison Reviewed-by: Tomas Elf Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_lrc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 3549ba608e6e..3d60823e2c20 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -2230,13 +2230,22 @@ int intel_lr_context_deferred_create(struct intel_context *ctx, lrc_setup_hardware_status_page(ring, ctx_obj); else if (ring->id == RCS && !ctx->rcs_initialized) { if (ring->init_context) { - ret = ring->init_context(ring, ctx); + struct drm_i915_gem_request *req; + + ret = i915_gem_request_alloc(ring, ctx, &req); + if (ret) + return ret; + + ret = ring->init_context(req->ring, ctx); if (ret) { DRM_ERROR("ring init context: %d\n", ret); + i915_gem_request_cancel(req); ctx->engine[ring->id].ringbuf = NULL; ctx->engine[ring->id].state = NULL; goto error; } + + i915_add_request_no_flush(req->ring); } ctx->rcs_initialized = true; -- GitLab