openwrt/target/linux/brcm2708/patches-4.19/950-0582-drm-vc4-Limit-fkms...

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Diff

From 06a0e398e7dcd6ba0a61713596c32ec6d43b47c8 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] 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
*/