not starting when using amd dedicated gpu

[lazywalker1]

System

Arch Linux: 5.11.11
i3-gaps: 4.19.1
linux-firmware: 20210315.3568f96
picom-git: 1578_Next.16.g9cb552e_2021.03.28
xorg-server: 1.20.10
mesa: 21.0.1

Configuration

shadow = false;
shadow-radius = 7;
shadow-offset-x = -7;
shadow-offset-y = -7;
shadow-exclude = [
"name = 'Notification'",
"class_g = 'Conky'",
"class_g ?= 'Notify-osd'",
"class_g = 'Cairo-clock'",
"_GTK_FRAME_EXTENTS@:c"
];
fading = false;
inactive-opacity = 0.8;
focus-exclude = [ "class_g = 'Cairo-clock'" ];
opacity-rule = [
"90:class_g = 'URxvt'",
"75:class_g = 'Polybar'"
]
corner-radius = 0
rounded-corners-exclude = [
"window_type = 'dock'",
"window_type = 'desktop'"
];
blur-method = "dual_kawase";
blur-strength = 3
blur-background = "true";
blur-kern = "3x3box";
blur-background-exclude = [
"window_type = 'dock'",
"window_type = 'desktop'",
"class_g = 'firefox'",
"_GTK_FRAME_EXTENTS@:c"
];
backend = "glx";
vsync = true;
mark-wmwin-focused = true;
detect-rounded-corners = true;
detect-client-opacity = true;
refresh-rate = 0;
detect-transient = true;
detect-client-leader = true;
glx-no-rebind-pixmap = true
use-damage = true;
wintypes:
{
tooltip = { fade = true; shadow = true; opacity = 0.75; focus = true; full-shadow = false; };
dock = { shadow = false; }
dnd = { shadow = false; }
popup_menu = { opacity = 0.8; }
dropdown_menu = { opacity = 0.8; }
};

I can run picom with integrated gpu. But, with dedicated AMD I can't use it. I am able to run it with xrender backend only. When I set glx as backend it gives me error. So, it throws me this error when I run DRI_PRIME=1 picom --experimental-backends:

[ glx_init ERROR ] GLX_EXT_texture_from_pixmap is not supported by your driver
[ initialize_backend FATAL ERROR ] Failed to initialize backend, aborting...

Output of glxinfo | grep -i "GLX_EXT_texture_from_pixmap":

GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating,
GLX_EXT_swap_control_tear, GLX_EXT_texture_from_pixmap,
GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating,

[IsaacMvmv]

Same... any help?

[yshui]

I believe it's currently not possible to use picom over PRIME, nothing I can do.

[nick87720z]

Could it be possible to use both GPU?

I tried with Intel HD 3000 + dedicated NVIDIA GT 620M. I remember, few years ago I got performance increase with nouveau, though I can't remember, if I got it with bumblebee, because now I used legacy x86-video-intel with prime as there (just ran single xrandr command to set gpu offload provider and that's all, while for optimus there's output source way).

However, this time I'm in 3x scale mode (3x bigger rendering scene, 4098x2304). Without compositor glxgears shows ~130fps with intel graphics and only 20 or 30 with DRI_PRIME=1. Could that there's no other reason to use it, than if discreete gpu had more efficient shader processing.

I originally hoped to get both gpu at the same time with xorg.conf options like AutoAddGPU, GPUDevice, but for now unsuccessful.