From 3e18c53e59457f585de217208e1745f2683be0b9 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Wed, 17 Jan 2018 14:16:04 -0800 Subject: [PATCH] i965: Bind null render targets for shadow sampling + color. Portal 2 appears to bind RGBA8888_UNORM textures to a sampler2DShadow, and calls shadow2D() on it. This causes undefined behavior in OpenGL. Unfortunately, our sampler appears to hang in this scenario, which is not acceptable. Just give them a null surface instead, which returns all zeroes. Fixes GPU hangs in Portal 2 on Kabylake. Huge thanks to Jason Ekstrand for noticing this crazy behavior while sifting through crash dumps. Cc: mesa-stable@lists.freedesktop.org Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104487 Reviewed-by: Topi Pohjolainen Reviewed-by: Jason Ekstrand --- .../drivers/dri/i965/brw_wm_surface_state.c | 33 ++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c index adf60a840b0..38af6bc0dea 100644 --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c @@ -1095,6 +1095,14 @@ const struct brw_tracked_state brw_renderbuffer_read_surfaces = { .emit = update_renderbuffer_read_surfaces, }; +static bool +is_depth_texture(struct intel_texture_object *iobj) +{ + GLenum base_format = _mesa_get_format_base_format(iobj->_Format); + return base_format == GL_DEPTH_COMPONENT || + (base_format == GL_DEPTH_STENCIL && !iobj->base.StencilSampling); +} + static void update_stage_texture_surfaces(struct brw_context *brw, const struct gl_program *prog, @@ -1121,9 +1129,32 @@ update_stage_texture_surfaces(struct brw_context *brw, if (prog->SamplersUsed & (1 << s)) { const unsigned unit = prog->SamplerUnits[s]; const bool used_by_txf = prog->info.textures_used_by_txf & (1 << s); + struct gl_texture_object *obj = ctx->Texture.Unit[unit]._Current; + struct intel_texture_object *iobj = intel_texture_object(obj); /* _NEW_TEXTURE */ - if (ctx->Texture.Unit[unit]._Current) { + if (!obj) + continue; + + if ((prog->ShadowSamplers & (1 << s)) && !is_depth_texture(iobj)) { + /* A programming note for the sample_c message says: + * + * "The Surface Format of the associated surface must be + * indicated as supporting shadow mapping as indicated in the + * surface format table." + * + * Accessing non-depth textures via a sampler*Shadow type is + * undefined. GLSL 4.50 page 162 says: + * + * "If a shadow texture call is made to a sampler that does not + * represent a depth texture, then results are undefined." + * + * We give them a null surface (zeros) for undefined. We've seen + * GPU hangs with color buffers and sample_c, so we try and avoid + * those with this hack. + */ + emit_null_surface_state(brw, NULL, surf_offset + s); + } else { brw_update_texture_surface(ctx, unit, surf_offset + s, for_gather, used_by_txf, plane); } -- 2.30.2