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Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0580-drm-vc4-Limit-fkms-to-modes-85Hz.patch')
-rw-r--r--target/linux/brcm2708/patches-4.19/950-0580-drm-vc4-Limit-fkms-to-modes-85Hz.patch26
1 files changed, 26 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0580-drm-vc4-Limit-fkms-to-modes-85Hz.patch b/target/linux/brcm2708/patches-4.19/950-0580-drm-vc4-Limit-fkms-to-modes-85Hz.patch
new file mode 100644
index 0000000000..b95a4db6d3
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0580-drm-vc4-Limit-fkms-to-modes-85Hz.patch
@@ -0,0 +1,26 @@
+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
+ */