opengl: Bail if cached shader fails to load

QOpenGLProgramBinaryCache::setProgramBinary() should check GL_LINK_STATUS after glProgramBinary(), but doesn't. In practice, this means that SDDM is a white screen, and KDE is just a gray task bar. So far, Qt tries to check this using its internal ::link() function. But in case the cached binary fails to load, Qt currently attempts to link the inexistent program, resulting in a zero-length, fixed pipeline shader. Checking this already in ::setProgramBinary() makes the call to ::link() superfluous, so we remove that as well. Done-with: Max Staudt <[email protected]> Done-with: Michal Srb <[email protected]> Done-with: Fabian Vogt <[email protected]> Task-number: QTBUG-66420 Change-Id: Iabb51d0eb2c0c16bde696efff623e57d15f28d82 Reviewed-by: Jesus Fernandez <[email protected]> Reviewed-by: Laszlo Agocs <[email protected]>
StrataSource · Feb 21, 2018 · fa09164 · fa09164
1 parent 22d3eee
commit fa09164
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Showing 2 changed files with 19 additions and 9 deletions.
diff --git a/src/gui/opengl/qopenglprogrambinarycache.cpp b/src/gui/opengl/qopenglprogrambinarycache.cpp
@@ -161,10 +161,26 @@ bool QOpenGLProgramBinaryCache::setProgramBinary(uint programId, uint blobFormat
     QOpenGLExtraFunctions *funcs = QOpenGLContext::currentContext()->extraFunctions();
     while (funcs->glGetError() != GL_NO_ERROR) { }
     funcs->glProgramBinary(programId, blobFormat, p, blobSize);
-    int err = funcs->glGetError();
+
+    GLenum err = funcs->glGetError();
+    if (err != GL_NO_ERROR) {
+        qCDebug(DBG_SHADER_CACHE, "Program binary failed to load for program %u, size %d, "
+                                  "format 0x%x, err = 0x%x",
+                programId, blobSize, blobFormat, err);
+        return false;
+    }
+    GLint linkStatus = 0;
+    funcs->glGetProgramiv(programId, GL_LINK_STATUS, &linkStatus);
+    if (linkStatus != GL_TRUE) {
+        qCDebug(DBG_SHADER_CACHE, "Program binary failed to load for program %u, size %d, "
+                                  "format 0x%x, linkStatus = 0x%x, err = 0x%x",
+                programId, blobSize, blobFormat, linkStatus, err);
+        return false;
+    }
+
     qCDebug(DBG_SHADER_CACHE, "Program binary set for program %u, size %d, format 0x%x, err = 0x%x",
             programId, blobSize, blobFormat, err);
-    return err == 0;
+    return true;
 }
 
 #ifdef Q_OS_UNIX

diff --git a/src/gui/opengl/qopenglshaderprogram.cpp b/src/gui/opengl/qopenglshaderprogram.cpp
@@ -3824,13 +3824,7 @@ bool QOpenGLShaderProgramPrivate::linkBinary()
     bool needsCompile = true;
     if (binCache.load(cacheKey, q->programId())) {
         qCDebug(DBG_SHADER_CACHE, "Program binary received from cache");
-        linkBinaryRecursion = true;
-        bool ok = q->link();
-        linkBinaryRecursion = false;
-        if (ok)
-            needsCompile = false;
-        else
-            qCDebug(DBG_SHADER_CACHE, "Link failed after glProgramBinary");
+        needsCompile = false;
     }
 
     bool needsSave = false;