aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/brcm2708/patches-4.19/950-0662-drm-vc4-Limit-fkms-to-modes-85Hz.patch
blob: 97d376c85db206bfcb4e607c4a2028a5ba007835 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
From d9656156d4c00d678e0c3a684af3f2fc953daf63 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.org>
Date: Tue, 18 Jun 2019 21:37:45 +0100
Subject: [PATCH 662/773] drm/vc4: Limit fkms to modes <= 85Hz

Selecting 1080p100 and 120 has very limited gain, but don't want
to block VGA85 and similar.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
---
 drivers/gpu/drm/vc4/vc4_firmware_kms.c | 4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/gpu/drm/vc4/vc4_firmware_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_firmware_kms.c
@@ -822,6 +822,10 @@ vc4_crtc_mode_valid(struct drm_crtc *crt
 		return MODE_NO_DBLESCAN;
 	}
 
+	/* Disable refresh rates > 85Hz as limited gain from them */
+	if (drm_mode_vrefresh(mode) > 85)
+		return MODE_BAD_VVALUE;
+
 	/* Limit the pixel clock based on the HDMI clock limits from the
 	 * firmware
 	 */