| From cd9063757a227cf31ebf5391ccda2bf583b0806e Mon Sep 17 00:00:00 2001 |
| From: Jernej Skrabec <jernej.skrabec@siol.net> |
| Date: Sun, 24 Mar 2019 20:06:09 +0100 |
| Subject: drm/sun4i: DW HDMI: Lower max. supported rate for H6 |
| |
| From: Jernej Skrabec <jernej.skrabec@siol.net> |
| |
| commit cd9063757a227cf31ebf5391ccda2bf583b0806e upstream. |
| |
| Currently resolutions with pixel clock higher than 340 MHz don't work |
| with H6 HDMI controller. They just produce a blank screen. |
| |
| Limit maximum pixel clock rate to 340 MHz until scrambling is supported. |
| |
| Cc: stable@vger.kernel.org # 5.0 |
| Fixes: 40bb9d3147b2 ("drm/sun4i: Add support for H6 DW HDMI controller") |
| Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net> |
| Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> |
| Link: https://patchwork.freedesktop.org/patch/msgid/20190324190609.32721-1-jernej.skrabec@siol.net |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c | 9 +++++++-- |
| 1 file changed, 7 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c |
| +++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c |
| @@ -48,8 +48,13 @@ static enum drm_mode_status |
| sun8i_dw_hdmi_mode_valid_h6(struct drm_connector *connector, |
| const struct drm_display_mode *mode) |
| { |
| - /* This is max for HDMI 2.0b (4K@60Hz) */ |
| - if (mode->clock > 594000) |
| + /* |
| + * Controller support maximum of 594 MHz, which correlates to |
| + * 4K@60Hz 4:4:4 or RGB. However, for frequencies greater than |
| + * 340 MHz scrambling has to be enabled. Because scrambling is |
| + * not yet implemented, just limit to 340 MHz for now. |
| + */ |
| + if (mode->clock > 340000) |
| return MODE_CLOCK_HIGH; |
| |
| return MODE_OK; |
