From ed7c5db8657d499d758e66da686231a9cfdd858a Mon Sep 17 00:00:00 2001
From: Arkadiusz Hiler <ahiler@codeweavers.com>
Date: Fri, 16 Jul 2021 17:21:35 +0300
Subject: [PATCH] docs: Add Vulkan section to PRIME.md.

---
 docs/PRIME.md | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/docs/PRIME.md b/docs/PRIME.md
index cadd839f..104926ef 100644
--- a/docs/PRIME.md
+++ b/docs/PRIME.md
@@ -60,6 +60,44 @@ In Steam set your game's Properties -> GENERAL -> LAUNCH OPTIONS to:
     __NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia %command%
 
 
+## Vulkan
+
+In case Vulkan games don't allow you to select a GPU or you experience
+problems with graphics APIs implemented on top of Vulkan you can limit or
+alter the GPU selection.
+
+### AMD -> Integrated Intel (Mesa -> Mesa)
+
+In Steam, set your game's Properties -> GENERAL -> LAUNCH OPTIONS to:
+
+    DRI_PRIME=1 %command%
+
+This will cause the devices to change order, i.e. the first GPU will swap
+places with another one.
+
+You can also limit the selection using Mesa's DEVICE_SELECT Vulkan layer. To
+list the GPUs:
+
+    $ MESA_VK_DEVICE_SELECT=list vulkaninfo
+    selectable devices:
+      GPU 0: 1002:67df "AMD RADV POLARIS10 (ACO)" discrete GPU 0000:01:00.0
+      GPU 1: 8086:412 "Intel(R) HD Graphics 4600 (HSW GT2)" integrated GPU 0000:00:02.0
+
+Then set the launch options using one of the vendor and product ids, e.g.:
+
+    DRI_PRIME=1 MESA_VK_DEVICE_SELECT=1002:67df $command%
+
+
+### Nvidia -> Integrated Intel (Nvidia's Proprietary Driver -> Mesa)
+
+In Steam set your game's Properties -> GENERAL -> LAUNCH OPTIONS to:
+
+    __NV_PRIME_RENDER_OFFLOAD=1 __VK_LAYER_NV_optimus=NVIDIA_only %command%
+
+This will load the Optimus Vulkan layer and use it to limit the GPU selection
+to NVIDIA only. Using `non_NVIDIA_only` will do the opposite.
+
+
 # Troubleshooting
 
 ## Performance