From 3b9c57cef4de80f29885e1edf69828de8d3fae6b Mon Sep 17 00:00:00 2001 From: Jonathan Liu Date: Tue, 9 Jan 2018 13:03:23 +1100 Subject: [PATCH] drm/sun4i: hdmi: Add missing rate halving check in sun4i_tmds_determine_rate It was only checking the divider when determing the closest match if it could not match the requested rate exactly. For a projector connected to an Olimex A20-OLinuXino-LIME using HDMI with a native resolution of 1280x800 and pixel clock of 83.5 MHz, this resulted in 1280x800 mode not being available and the following in dmesg when the kernel is booted with drm.debug=0x3e: [drm:drm_mode_debug_printmodeline] Modeline 37:"1280x800" 60 83500 1280 1352 1480 1680 800 810 816 831 0x48 0x5 [drm:drm_mode_prune_invalid] Not using 1280x800 mode: NOCLOCK Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support") Signed-off-by: Jonathan Liu Signed-off-by: Maxime Ripard Link: https://patchwork.freedesktop.org/patch/msgid/20180109020323.11852-4-net147@gmail.com --- drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c index 88eeeaf34638..3ecffa52c814 100644 --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c @@ -102,9 +102,12 @@ static int sun4i_tmds_determine_rate(struct clk_hw *hw, goto out; } - if (!best_parent || abs(rate - rounded / i) < - abs(rate - best_parent / best_div)) { + if (!best_parent || + abs(rate - rounded / i / j) < + abs(rate - best_parent / best_half / + best_div)) { best_parent = rounded; + best_half = i; best_div = j; } } -- 2.45.2