From 662273397c537d031e1aee7c607c925ec6bb2d10 Mon Sep 17 00:00:00 2001 From: "Lukas F. Hartmann" Date: Tue, 15 May 2018 21:51:56 +0200 Subject: [PATCH] glamor_init: clamp GLSL to 120 if platform doesn't have instanced arrays Hi, I upgraded Xwayland and the assorted libraries from git masters today, and noticed that glamor wouldn't work anymore on i.MX6/etnaviv. The error was: No provider of glVertexAttribDivisor found. Requires one of: Desktop OpenGL 3.3 OpenGL ES 3.0 GL extension "GL_ANGLE_instanced_arrays" GL extension "GL_ARB_instanced_arrays" GL extension "GL_EXT_instanced_arrays" GL extension "GL_NV_instanced_arrays" The problem is that etnaviv offers GLSL 140 on GL 2.1 and glamor rendering assumes that glVertexAttribDivisor() is always available on GLSL>=130, which is not the case here. Forcing GLSL 120 makes glamor work fine again on this platform. After chatting with ajax in #xorg-devel, the following solution was proposed. This is my first time of submitting a patch, so please excuse me and advise if I'm doing it wrong ;) Cheers Lukas (mntmn) Reviewed-by: Eric Anholt (cherry picked from commit 7437b6dbdee050f8ebb3a79b9077d051c91880c3) --- glamor/glamor.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/glamor/glamor.c b/glamor/glamor.c index 86935ed98..d984d20f3 100644 --- a/glamor/glamor.c +++ b/glamor/glamor.c @@ -563,6 +563,14 @@ glamor_init(ScreenPtr screen, unsigned int flags) if (!glamor_check_instruction_count(gl_version)) goto fail; + + /* Glamor rendering assumes that platforms with GLSL 130+ + * have instanced arrays, but this is not always the case. + * etnaviv offers GLSL 140 with OpenGL 2.1. + */ + if (glamor_priv->glsl_version >= 130 && + !epoxy_has_gl_extension("GL_ARB_instanced_arrays")) + glamor_priv->glsl_version = 120; } else { if (gl_version < 20) { ErrorF("Require Open GLES2.0 or later.\n");