gpu fb startup analysis - mehome/openthos GitHub Wiki
#理解gpu fb初始化 在用qemu模拟执行时，看到没有识别出qemu支持的virtio-gpu，这部分代码位于
01-11 07:36:40.060 1104 1104 D libEGL : 3D hardware acceleration is disabled
01-11 07:36:40.060 1104 1104 D libEGL : Emulator without GPU support detected. Fallback to software renderer.
查找字符串，可以定位到源码 framework/native/opengl/libs/EGL/Loader.cpp中checkGlesEmulationStatus(void)函数
/* This function is called to check whether we run inside the emulator,
* and if this is the case whether GLES GPU emulation is supported.
*
* Returned values are:
* -1 -> not running inside the emulator
* 0 -> running inside the emulator, but GPU emulation not supported
* 1 -> running inside the emulator, GPU emulation is supported
* through the "emulation" config.
*/
static int
checkGlesEmulationStatus(void)
{
/* We're going to check for the following kernel parameters:
*
* qemu=1 -> tells us that we run inside the emulator
* android.qemu.gles=<number> -> tells us the GLES GPU emulation status
*
* Note that we will return <number> if we find it. This let us support
* more additionnal emulation modes in the future.
*/
char prop[PROPERTY_VALUE_MAX];
int result = -1;
/* Check if hardware acceleration disabled explicitly */
property_get("debug.egl.hw", prop, "1");
if (!atoi(prop)) {
ALOGD("3D hardware acceleration is disabled");
return 0;
}
/* First, check for qemu=1 */
property_get("ro.kernel.qemu",prop,"0");
if (atoi(prop) != 1)
return -1;
/* We are in the emulator, get GPU status value */
property_get("ro.kernel.qemu.gles",prop,"0");
return atoi(prop);
}
而在getprop命令的输出中，可以看到
[ro.kernel.qemu]: [1]
而ro.kernel.qemu.gles的设置决定了qemu是否支持opengl 在目前的getprop中，找不到这个属性。