queue-4.14/drm-arm-hdlcd-actually-validate-crtc-modes.patch

   1 From 97cb5df6d43cedb16b9fdd12464d87f1fe58b0d4 Mon Sep 17 00:00:00 2001
   2 From: Robin Murphy <robin.murphy@arm.com>
   3 Date: Fri, 17 May 2019 17:37:21 +0100
   4 Subject: drm/arm/hdlcd: Actually validate CRTC modes
   5
   6 [ Upstream commit b96151edced4edb6a18aa89a5fa02c7066efff45 ]
   7
   8 Rather than allowing any old mode through, then subsequently refusing
   9 unmatchable clock rates in atomic_check when it's too late to back out
  10 and pick a different mode, let's do that validation up-front where it
  11 will cause unsupported modes to be correctly pruned in the first place.
  12
  13 This also eliminates an issue whereby a perceived clock rate of 0 would
  14 cause atomic disable to fail and prevent the module from being unloaded.
  15
  16 Signed-off-by: Robin Murphy <robin.murphy@arm.com>
  17 Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
  18 Signed-off-by: Sasha Levin <sashal@kernel.org>
  19 ---
  20  drivers/gpu/drm/arm/hdlcd_crtc.c | 11 +++++------
  21  1 file changed, 5 insertions(+), 6 deletions(-)
  22
  23 diff --git a/drivers/gpu/drm/arm/hdlcd_crtc.c b/drivers/gpu/drm/arm/hdlcd_crtc.c
  24 index 72b22b805412..4a108660cc8f 100644
  25 --- a/drivers/gpu/drm/arm/hdlcd_crtc.c
  26 +++ b/drivers/gpu/drm/arm/hdlcd_crtc.c
  27 @@ -186,20 +186,19 @@ static void hdlcd_crtc_atomic_disable(struct drm_crtc *crtc,
  28         clk_disable_unprepare(hdlcd->clk);
  29  }
  30
  31 -static int hdlcd_crtc_atomic_check(struct drm_crtc *crtc,
  32 -                                  struct drm_crtc_state *state)
  33 +static enum drm_mode_status hdlcd_crtc_mode_valid(struct drm_crtc *crtc,
  34 +               const struct drm_display_mode *mode)
  35  {
  36         struct hdlcd_drm_private *hdlcd = crtc_to_hdlcd_priv(crtc);
  37 -       struct drm_display_mode *mode = &state->adjusted_mode;
  38         long rate, clk_rate = mode->clock * 1000;
  39
  40         rate = clk_round_rate(hdlcd->clk, clk_rate);
  41         if (rate != clk_rate) {
  42                 /* clock required by mode not supported by hardware */
  43 -               return -EINVAL;
  44 +               return MODE_NOCLOCK;
  45         }
  46
  47 -       return 0;
  48 +       return MODE_OK;
  49  }
  50
  51  static void hdlcd_crtc_atomic_begin(struct drm_crtc *crtc,
  52 @@ -220,7 +219,7 @@ static void hdlcd_crtc_atomic_begin(struct drm_crtc *crtc,
  53  }
  54
  55  static const struct drm_crtc_helper_funcs hdlcd_crtc_helper_funcs = {
  56 -       .atomic_check   = hdlcd_crtc_atomic_check,
  57 +       .mode_valid     = hdlcd_crtc_mode_valid,
  58         .atomic_begin   = hdlcd_crtc_atomic_begin,
  59         .atomic_enable  = hdlcd_crtc_atomic_enable,
  60         .atomic_disable = hdlcd_crtc_atomic_disable,
  61 --
  62 2.20.1
  63