target/linux/bcm27xx/patches-5.15/950-0441-drm-vc4-Increase-the-core-clock-based-on-HVS-load.patch

   1 From 7971426f2462b02ea1bf12d902ca066e07eeb64b Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime@cerno.tech>
   3 Date: Wed, 26 May 2021 16:13:02 +0200
   4 Subject: [PATCH] drm/vc4: Increase the core clock based on HVS load
   5
   6 Depending on a given HVS output (HVS to PixelValves) and input (planes
   7 attached to a channel) load, the HVS needs for the core clock to be
   8 raised above its boot time default.
   9
  10 Failing to do so will result in a vblank timeout and a stalled display
  11 pipeline.
  12
  13 Signed-off-by: Maxime Ripard <maxime@cerno.tech>
  14 ---
  15  drivers/gpu/drm/vc4/vc4_drv.h |  1 +
  16  drivers/gpu/drm/vc4/vc4_kms.c | 13 +++++++++++++
  17  2 files changed, 14 insertions(+)
  18
  19 --- a/drivers/gpu/drm/vc4/vc4_drv.h
  20 +++ b/drivers/gpu/drm/vc4/vc4_drv.h
  21 @@ -321,6 +321,7 @@ struct vc4_hvs {
  22         u32 __iomem *dlist;
  23
  24         struct clk *core_clk;
  25 +       struct clk_request *core_req;
  26
  27         /* Memory manager for CRTCs to allocate space in the display
  28          * list.  Units are dwords.
  29 --- a/drivers/gpu/drm/vc4/vc4_kms.c
  30 +++ b/drivers/gpu/drm/vc4/vc4_kms.c
  31 @@ -391,6 +391,11 @@ static void vc4_atomic_commit_tail(struc
  32                                                 new_hvs_state->core_clock_rate);
  33
  34                 core_req = clk_request_start(hvs->core_clk, core_rate);
  35 +               /*
  36 +                * And remove the previous one based on the HVS
  37 +                * requirements if any.
  38 +                */
  39 +               clk_request_done(hvs->core_req);
  40         }
  41
  42         drm_atomic_helper_commit_modeset_disables(dev, state);
  43 @@ -418,6 +423,14 @@ static void vc4_atomic_commit_tail(struc
  44                 drm_dbg(dev, "Running the core clock at %lu Hz\n",
  45                         new_hvs_state->core_clock_rate);
  46
  47 +               /*
  48 +                * Request a clock rate based on the current HVS
  49 +                * requirements.
  50 +                */
  51 +               hvs->core_req = clk_request_start(hvs->core_clk,
  52 +                                                 new_hvs_state->core_clock_rate);
  53 +
  54 +               /* And drop the temporary request */
  55                 clk_request_done(core_req);
  56         }
  57  }