From 4396393fb96449c56423fb4b351f76e45a6bcaf6 Mon Sep 17 00:00:00 2001 From: Chen-Yu Tsai Date: Tue, 7 Jan 2020 15:01:13 +0800 Subject: [PATCH] drm/sun4i: tcon: Set RGB DCLK min. divider based on hardware model In commit 0b8e7bbde5e7 ("drm/sun4i: tcon: Set min division of TCON0_DCLK to 1.") it was assumed that all TCON variants support a minimum divider of 1 if only DCLK was used. However, the oldest generation of hardware only supports minimum divider of 4 if only DCLK is used. If a divider of 1 was used on this old hardware, some scrolling artifact would appear. A divider of 2 seemed OK, but a divider of 3 had artifacts as well. Set the minimum divider when outputing to parallel RGB based on the hardware model, with a minimum of 4 for the oldest (A10/A10s/A13/A20) hardware, and a minimum of 1 for the rest. A value is not set for the TCON variants lacking channel 0. This fixes the scrolling artifacts seen on my A13 tablet. Fixes: 0b8e7bbde5e7 ("drm/sun4i: tcon: Set min division of TCON0_DCLK to 1.") Cc: # 5.4.x Signed-off-by: Chen-Yu Tsai Signed-off-by: Maxime Ripard Link: https://patchwork.freedesktop.org/patch/msgid/20200107070113.28951-1-wens@kernel.org --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 15 ++++++++++++--- drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 + 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index 42651d7..c81cdce 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -489,7 +489,7 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon, WARN_ON(!tcon->quirks->has_channel_0); - tcon->dclk_min_div = 1; + tcon->dclk_min_div = tcon->quirks->dclk_min_div; tcon->dclk_max_div = 127; sun4i_tcon0_mode_set_common(tcon, mode); @@ -1426,12 +1426,14 @@ static int sun8i_r40_tcon_tv_set_mux(struct sun4i_tcon *tcon, static const struct sun4i_tcon_quirks sun4i_a10_quirks = { .has_channel_0 = true, .has_channel_1 = true, + .dclk_min_div = 4, .set_mux = sun4i_a10_tcon_set_mux, }; static const struct sun4i_tcon_quirks sun5i_a13_quirks = { .has_channel_0 = true, .has_channel_1 = true, + .dclk_min_div = 4, .set_mux = sun5i_a13_tcon_set_mux, }; @@ -1440,6 +1442,7 @@ static const struct sun4i_tcon_quirks sun6i_a31_quirks = { .has_channel_1 = true, .has_lvds_alt = true, .needs_de_be_mux = true, + .dclk_min_div = 1, .set_mux = sun6i_tcon_set_mux, }; @@ -1447,11 +1450,13 @@ static const struct sun4i_tcon_quirks sun6i_a31s_quirks = { .has_channel_0 = true, .has_channel_1 = true, .needs_de_be_mux = true, + .dclk_min_div = 1, }; static const struct sun4i_tcon_quirks sun7i_a20_quirks = { .has_channel_0 = true, .has_channel_1 = true, + .dclk_min_div = 4, /* Same display pipeline structure as A10 */ .set_mux = sun4i_a10_tcon_set_mux, }; @@ -1459,11 +1464,13 @@ static const struct sun4i_tcon_quirks sun7i_a20_quirks = { static const struct sun4i_tcon_quirks sun8i_a33_quirks = { .has_channel_0 = true, .has_lvds_alt = true, + .dclk_min_div = 1, }; static const struct sun4i_tcon_quirks sun8i_a83t_lcd_quirks = { .supports_lvds = true, .has_channel_0 = true, + .dclk_min_div = 1, }; static const struct sun4i_tcon_quirks sun8i_a83t_tv_quirks = { @@ -1477,11 +1484,13 @@ static const struct sun4i_tcon_quirks sun8i_r40_tv_quirks = { static const struct sun4i_tcon_quirks sun8i_v3s_quirks = { .has_channel_0 = true, + .dclk_min_div = 1, }; static const struct sun4i_tcon_quirks sun9i_a80_tcon_lcd_quirks = { - .has_channel_0 = true, - .needs_edp_reset = true, + .has_channel_0 = true, + .needs_edp_reset = true, + .dclk_min_div = 1, }; static const struct sun4i_tcon_quirks sun9i_a80_tcon_tv_quirks = { diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h index f9f1fe80..a62ec82 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.h +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h @@ -224,6 +224,7 @@ struct sun4i_tcon_quirks { bool needs_de_be_mux; /* sun6i needs mux to select backend */ bool needs_edp_reset; /* a80 edp reset needed for tcon0 access */ bool supports_lvds; /* Does the TCON support an LVDS output? */ + u8 dclk_min_div; /* minimum divider for TCON0 DCLK */ /* callback to handle tcon muxing options */ int (*set_mux)(struct sun4i_tcon *, const struct drm_encoder *); -- 2.7.4