Comment 3 for bug 1947820

I tried to apply the patch in https://gitlab.freedesktop.org/xorg/xserver/-/issues/1028 . But it didn't work for the delay phenomenon.

From 346e44407dc0beeed1e1ef3eebeeaa0bae2b3ac1 Mon Sep 17 00:00:00 2001
From: Lukasz Spintzyk <email address hidden>
Date: Mon, 18 May 2020 13:29:54 +0200
Subject: [PATCH] Fix for DisplayLink screens refresing with 1FPS

This is fixing issue described here:
https://gitlab.freedesktop.org/xorg/xserver/-/issues/1028

This commit is modifying ms_randr_crtc_covering_drawable introduced in commit:
Since https://gitlab.freedesktop.org/xorg/xserver/-/commit/325f694e97a117aec47aa2e1a9b2b28c3c47994e

Since ms_randr_crtc_covering_drawable intended to be RandR-based implementation of ms_dri2_crtc_covering_drawable
it is still using ms_first_output whereas RRFirstOutput replacement is aval
---
 hw/xfree86/drivers/modesetting/vblank.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/xfree86/drivers/modesetting/vblank.c b/hw/xfree86/drivers/modesetting/vblank.c
index 50d2fd3a4..a0d62e8b4 100644
--- a/hw/xfree86/drivers/modesetting/vblank.c
+++ b/hw/xfree86/drivers/modesetting/vblank.c
@@ -266,7 +266,7 @@ ms_covering_randr_crtc(ScreenPtr pScreen, BoxPtr box, Bool screen_is_ms)
         ScreenPtr slave;

         if (dixPrivateKeyRegistered(rrPrivKey))
- primary_output = ms_first_output(scrn->pScreen);
+ primary_output = RRFirstOutput(scrn->pScreen);
         if (!primary_output || !primary_output->crtc)
             return NULL;