patches/kernel/0018-drm-mgag200-Fix-PLL-setup-for-G200_SE_A-rev-4.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Jocelyn Falempe <jfalempe@redhat.com>
   3 Date: Thu, 13 Oct 2022 15:28:10 +0200
   4 Subject: [PATCH] drm/mgag200: Fix PLL setup for G200_SE_A rev >=4
   5
   6 commit b389286d0234e1edbaf62ed8bc0892a568c33662 upstream.
   7
   8 For G200_SE_A, PLL M setting is wrong, which leads to blank screen,
   9 or "signal out of range" on VGA display.
  10 previous code had "m |= 0x80" which was changed to
  11 m |= ((pixpllcn & BIT(8)) >> 1);
  12
  13 Tested on G200_SE_A rev 42
  14
  15 This line of code was moved to another file with
  16 commit 877507bb954e ("drm/mgag200: Provide per-device callbacks for
  17 PIXPLLC") but can be easily backported before this commit.
  18
  19 v2: * put BIT(7) First to respect MSB-to-LSB (Thomas)
  20     * Add a comment to explain that this bit must be set (Thomas)
  21
  22 Fixes: 2dd040946ecf ("drm/mgag200: Store values (not bits) in struct mgag200_pll_values")
  23 Cc: stable@vger.kernel.org
  24 Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
  25 Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
  26 Link: https://patchwork.freedesktop.org/patch/msgid/20221013132810.521945-1-jfalempe@redhat.com
  27 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  28 (cherry picked from commit 3650c063f22d03795026bd6f3d473e5bbdabb442)
  29 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
  30 ---
  31  drivers/gpu/drm/mgag200/mgag200_g200se.c | 3 ++-
  32  1 file changed, 2 insertions(+), 1 deletion(-)
  33
  34 diff --git a/drivers/gpu/drm/mgag200/mgag200_g200se.c b/drivers/gpu/drm/mgag200/mgag200_g200se.c
  35 index be389ed91cbd..bd6e573c9a1a 100644
  36 --- a/drivers/gpu/drm/mgag200/mgag200_g200se.c
  37 +++ b/drivers/gpu/drm/mgag200/mgag200_g200se.c
  38 @@ -284,7 +284,8 @@ static void mgag200_g200se_04_pixpllc_atomic_update(struct drm_crtc *crtc,
  39         pixpllcp = pixpllc->p - 1;
  40         pixpllcs = pixpllc->s;
  41
  42 -       xpixpllcm = pixpllcm | ((pixpllcn & BIT(8)) >> 1);
  43 +       // For G200SE A, BIT(7) should be set unconditionally.
  44 +       xpixpllcm = BIT(7) | pixpllcm;
  45         xpixpllcn = pixpllcn;
  46         xpixpllcp = (pixpllcs << 3) | pixpllcp;
  47