releases/5.0.8/drm-sun4i-dw-hdmi-lower-max.-supported-rate-for-h6.patch

   1 From cd9063757a227cf31ebf5391ccda2bf583b0806e Mon Sep 17 00:00:00 2001
   2 From: Jernej Skrabec <jernej.skrabec@siol.net>
   3 Date: Sun, 24 Mar 2019 20:06:09 +0100
   4 Subject: drm/sun4i: DW HDMI: Lower max. supported rate for H6
   5
   6 From: Jernej Skrabec <jernej.skrabec@siol.net>
   7
   8 commit cd9063757a227cf31ebf5391ccda2bf583b0806e upstream.
   9
  10 Currently resolutions with pixel clock higher than 340 MHz don't work
  11 with H6 HDMI controller. They just produce a blank screen.
  12
  13 Limit maximum pixel clock rate to 340 MHz until scrambling is supported.
  14
  15 Cc: stable@vger.kernel.org # 5.0
  16 Fixes: 40bb9d3147b2 ("drm/sun4i: Add support for H6 DW HDMI controller")
  17 Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
  18 Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
  19 Link: https://patchwork.freedesktop.org/patch/msgid/20190324190609.32721-1-jernej.skrabec@siol.net
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21
  22 ---
  23  drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c |    9 +++++++--
  24  1 file changed, 7 insertions(+), 2 deletions(-)
  25
  26 --- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
  27 +++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
  28 @@ -48,8 +48,13 @@ static enum drm_mode_status
  29  sun8i_dw_hdmi_mode_valid_h6(struct drm_connector *connector,
  30                             const struct drm_display_mode *mode)
  31  {
  32 -       /* This is max for HDMI 2.0b (4K@60Hz) */
  33 -       if (mode->clock > 594000)
  34 +       /*
  35 +        * Controller support maximum of 594 MHz, which correlates to
  36 +        * 4K@60Hz 4:4:4 or RGB. However, for frequencies greater than
  37 +        * 340 MHz scrambling has to be enabled. Because scrambling is
  38 +        * not yet implemented, just limit to 340 MHz for now.
  39 +        */
  40 +       if (mode->clock > 340000)
  41                 return MODE_CLOCK_HIGH;
  42
  43         return MODE_OK;