From 7a79279e7186c4ac8b753cbd335ecc4ba81b5970 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 22 Nov 2016 13:56:54 +0000 Subject: [PATCH] drm/arm: hdlcd: fix plane base address update While testing HDMI with Xorg on the Juno board, I find that when Xorg starts up or shuts down, the display is shifted significantly to the right and wrapped in the active region. (No sync bars are visible.) The timings are correct, it behaves as if the start address has been shifted many pixels _into_ the framebuffer. This occurs whenever the display mode size is changed - using xrandr in Xorg shows that changing the resolution triggers the problem almost every time, but changing the refresh rate does not. Using devmem2 to disable and re-enable the HDLCD resolves the issue, and repeated disable/enable cycles do not make the issue re-appear. Further debugging shows that we try to update the controller configuration while enabled. Alwys ensure that the HDLCD is disabled prior to updating the controller timings, and use drm_crtc_vblank_off()/drm_crtc_vblank_on() so that DRM knows whether it can expect vblank interrupts. Signed-off-by: Russell King Signed-off-by: Liviu Dudau --- drivers/gpu/drm/arm/hdlcd_crtc.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/arm/hdlcd_crtc.c b/drivers/gpu/drm/arm/hdlcd_crtc.c index 48019ae22ddb..28341b32067f 100644 --- a/drivers/gpu/drm/arm/hdlcd_crtc.c +++ b/drivers/gpu/drm/arm/hdlcd_crtc.c @@ -150,15 +150,14 @@ static void hdlcd_crtc_enable(struct drm_crtc *crtc) clk_prepare_enable(hdlcd->clk); hdlcd_crtc_mode_set_nofb(crtc); hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 1); + drm_crtc_vblank_on(crtc); } static void hdlcd_crtc_disable(struct drm_crtc *crtc) { struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc); - if (!crtc->state->active) - return; - + drm_crtc_vblank_off(crtc); hdlcd_write(hdlcd, HDLCD_REG_COMMAND, 0); clk_disable_unprepare(hdlcd->clk); } -- 2.30.2