Some LCD controller cannot provide valid VESA style sync, i.e. coincident HS/VS edges. First, this patch adds hskew passed from the adjusted_mode to reference pixel calculation to allow those controllers to add an offset relative to the expected reference pixel.
Signed-off-by: Darren Etheridge detheridge@ti.com Signed-off-by: Sebastian Hesselbarth sebastian.hesselbarth@gmail.com --- Changelog: for v1: - reword comment
Cc: David Airlie airlied@linux.ie Cc: Darren Etheridge detheridge@ti.com Cc: Rob Clark robdclark@gmail.com Cc: Russell King rmk+kernel@arm.linux.org.uk Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org --- drivers/gpu/drm/i2c/tda998x_drv.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c index 92fcb3d..c2bd711 100644 --- a/drivers/gpu/drm/i2c/tda998x_drv.c +++ b/drivers/gpu/drm/i2c/tda998x_drv.c @@ -782,6 +782,14 @@ tda998x_encoder_mode_set(struct drm_encoder *encoder, de_pix_s = mode->htotal - mode->hdisplay; ref_pix = 3 + hs_pix_s;
+ /* + * Attached LCD controllers may generate broken sync. Allow + * those to adjust the position of the rising VS edge by adding + * HSKEW to ref_pix. + */ + if (adjusted_mode->flags & DRM_MODE_FLAG_HSKEW) + ref_pix += adjusted_mode->hskew; + if ((mode->flags & DRM_MODE_FLAG_INTERLACE) == 0) { ref_line = 1 + mode->vsync_start - mode->vdisplay; vwin1_line_s = mode->vtotal - mode->vdisplay - 1;