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[2/2] drm/amdgpu: make sure vertical front porch is at least 1

Message ID 1462301534-6821-2-git-send-email-alexander.deucher@amd.com (mailing list archive)
State New, archived
Headers show

Commit Message

Alex Deucher May 3, 2016, 6:52 p.m. UTC 
hw doesn't like a 0 value.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/amd/amdgpu/atombios_encoders.c | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c b/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
index 1e0bba2..1cd6de5 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
@@ -298,6 +298,10 @@  bool amdgpu_atombios_encoder_mode_fixup(struct drm_encoder *encoder,
 	    && (mode->crtc_vsync_start < (mode->crtc_vdisplay + 2)))
 		adjusted_mode->crtc_vsync_start = adjusted_mode->crtc_vdisplay + 2;
 
+	/* vertical FP must be at least 1 */
+	if (mode->crtc_vsync_start == mode->crtc_vdisplay)
+		adjusted_mode->crtc_vsync_start++;
+
 	/* get the native mode for scaling */
 	if (amdgpu_encoder->active_device & (ATOM_DEVICE_LCD_SUPPORT))
 		amdgpu_panel_mode_fixup(encoder, adjusted_mode);