target/linux/bcm27xx/patches-5.15/950-0431-drm-vc4-Change-the-default-DPI-format-to-being-18bpp.patch

   1 From bf6ce41170822705037cc070b89a85ac4e6a4645 Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Fri, 12 Feb 2021 17:31:37 +0000
   4 Subject: [PATCH] drm/vc4: Change the default DPI format to being
   5  18bpp, not 24.
   6
   7 DPI hasn't really been used up until now, so the default has
   8 been meaningless.
   9 In theory we should be able to pass the desired format for the
  10 adjacent bridge chip through, but framework seems to be missing
  11 for that.
  12
  13 As the main device to use DPI is the VGA666 or Adafruit Kippah,
  14 both of which use RGB666, change the default to being RGB666 instead
  15 of RGB888.
  16
  17 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  18 ---
  19  drivers/gpu/drm/vc4/vc4_dpi.c | 4 ++--
  20  1 file changed, 2 insertions(+), 2 deletions(-)
  21
  22 --- a/drivers/gpu/drm/vc4/vc4_dpi.c
  23 +++ b/drivers/gpu/drm/vc4/vc4_dpi.c
  24 @@ -198,8 +198,8 @@ static void vc4_dpi_encoder_enable(struc
  25                 if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW)
  26                         dpi_c |= DPI_OUTPUT_ENABLE_INVERT;
  27         } else {
  28 -               /* Default to 24bit if no connector found. */
  29 -               dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);
  30 +               /* Default to 18bit if no connector found. */
  31 +               dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1, DPI_FORMAT);
  32         }
  33
  34         if (mode->flags & DRM_MODE_FLAG_NHSYNC)