Intel uhd 620 不支持 opengl 4，Ubuntu 18.04

Question

我最近买了一台戴尔 Inspiron 15" 5570，该版本配备英特尔 i5 8250u 和 iGPU 英特尔 UHD 620。安装 Ubuntu 后，我的屏幕有些闪烁，我使用Joakim 的解决方法但现在我又遇到了另一个我无法解决的问题。我需要 OpenGL 4，集成的 gpu 支持它，但我不知道如何“启用”它。这是输出glxinfo | grep -i opengl：

glxinfo | grep -i opengl
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2) 
OpenGL core profile version string: 4.5 (Core Profile) Mesa 18.2.0-devel
OpenGL core profile shading language version string: 4.50
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 18.2.0-devel
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.2 Mesa 18.2.0-devel
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20
OpenGL ES profile extensions:

这是另一个可能有用的 glxinfo 部分：

Extended renderer info (GLX_MESA_query_renderer):
    Vendor: Intel Open Source Technology Center (0x8086)
    Device: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2)  (0x5917)
    Version: 18.2.0
    Accelerated: yes
    Video memory: 3072MB
    Unified memory: yes
    Preferred profile: core (0x1)
    Max core profile version: 4.5
    Max compat profile version: 3.0
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.2

这是我尝试启动需要 opengl 4 的程序时的输出错误：

X Error of failed request:  GLXBadFBConfig
  Major opcode of failed request:  155 (GLX)
  Minor opcode of failed request:  34 ()
  Serial number of failed request:  40
  Current serial number in output stream:  39

我听说过这样的 alpha 启动选项可以为我的 CPU 启用 alpha 驱动程序，但是我错过了，在此先感谢您的帮助。

--更新--我实际上“处理”了这个错误，我尝试了其他需要 openGL 4 功能、openGL 4.5 上下文的程序，并且运行正常，但是当我想使用这个需要 4.5 上下文的“遗留”OpenGL 程序时

#include <cstdlib>
#include <cmath>
#include <iostream>

#ifdef __APPLE__
#  include <GL/glew.h>
#  include <GL/freeglut.h>
#  include <OpenGL/glext.h>
#else
#  include <GL/glew.h>
#  include <GL/freeglut.h>
#  include <GL/glext.h>
#pragma comment(lib, "glew32.lib")
#endif

#define PI 3.14159265358979324

using namespace std;

// Globals.
static float R = 40.0; // Radius of circle.
static float X = 50.0; // X-coordinate of center of circle.
static float Y = 50.0; // Y-coordinate of center of circle.
static int numVertices = 10; // Number of vertices on circle.

// Drawing routine.
void drawScene(void)
{
   float t = 0; // Angle parameter.

   glClear(GL_COLOR_BUFFER_BIT);

   glColor3f(0.0, 0.0, 0.0);

   // Draw a line loop with vertices at equal angles apart on a circle
   // with center at (X, Y) and radius R, The vertices are colored randomly.
   /* Funzione seno esercizio pag56 2.27
   glBegin(GL_LINE_STRIP);
      for(float i = -PI; i <= PI; i+=PI/20.0)
      {
     glColor3f((float)rand()/(float)RAND_MAX, (float)rand()/(float)RAND_MAX, (float)rand()/(float)RAND_MAX);
     glVertex3f(i, sin(i), 0.0);
     //cout<<"x="<<i<<";y="<<sin(i);
     //t += 2 * PI / numVertices;
      }
   glEnd();*/
   //Ellisse esercizio pag56 2.28
   //x = X + A*cos(t), y = Y + B*sin(t), z=0,  0<=t<=2PI
   glBegin(GL_LINE_LOOP);
      for(int i = 0; i < numVertices; i++)
   {
     glColor3f((float)rand()/(float)RAND_MAX, (float)rand()/(float)RAND_MAX, (float)rand()/(float)RAND_MAX);
     glVertex3f((R+10)*cos(t), (R-10)*sin(t), 0.0);
     //cout<<"x="<<i<<";y="<<sin(i);
     t += 2 * PI / numVertices;
   }
   glEnd();

   glFlush();
}

// Initialization routine.
void setup(void)
{
   glClearColor(1.0, 1.0, 1.0, 0.0);
}

// OpenGL window reshape routine.
void resize(int w, int h)
{
   glViewport(0, 0, w, h);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glOrtho(-50, 50, -50, 50, -1.0, 1.0);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}

// Keyboard input processing routine.
void keyInput(unsigned char key, int x, int y)
{
   switch(key)
   {
      case 27:
     exit(0);
     break;
      case '+':
     numVertices++;
     glutPostRedisplay();
     break;
      case '-':
     if (numVertices > 3) numVertices--;
     glutPostRedisplay();
     break;
      default:
     break;
   }
}

// Routine to output interaction instructions to the C++ window.
void printInteraction(void)
{
   cout << "Interaction:" << endl;
   cout << "Press +/- to increase/decrease the number of vertices on the circle." << endl;
}

// Main routine.
int main(int argc, char **argv)
{
   printInteraction();
   glutInit(&argc, argv);

   glutInitContextVersion(4,5);
   glutInitContextProfile(GLUT_COMPATIBILITY_PROFILE);

   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGBA);
   glutInitWindowSize(500, 500);
   glutInitWindowPosition(100, 100);
   glutCreateWindow("circle.cpp");
   glutDisplayFunc(drawScene);
   glutReshapeFunc(resize);
   glutKeyboardFunc(keyInput);

   glewExperimental = GL_TRUE;
   glewInit();

   setup();

   glutMainLoop();
}

给出错误：

X Error of failed request:  GLXBadFBConfig
  Major opcode of failed request:  155 (GLX)
  Minor opcode of failed request:  34 ()
  Serial number of failed request:  40

但我实际上可以通过如下方式启动它来使用它：

MESA_GL_VERSION_OVERRIDE=4.5 ./circle 

我不知道为什么这可能是一个错误，因为当我尝试编译其他程序时，这些程序在没有 MESA.. 前缀的情况下运行，使用：glutInitContextVersion(4, 6); 而不是：glutInitContextVersion(4, 5); 它给出了相同的 GLXBadFBConfig 错误，因此程序本身没有任何 OpenGL 错误上下文设置缓解。