target/linux/bcm27xx/patches-5.4/950-0253-drm-vc4-handle-the-case-where-there-are-no-available.patch

   1 From 1fbbd377bd1c6b4e3342d03091f19089ccb7fcbe Mon Sep 17 00:00:00 2001
   2 From: Jonathan Bell <jonathan@raspberrypi.org>
   3 Date: Tue, 28 May 2019 13:56:06 +0100
   4 Subject: [PATCH] drm: vc4: handle the case where there are no
   5  available displays
   6
   7 It's reasonable for the firmware to return zero as the number of
   8 attached displays. Handle this case as otherwise drm thinks that
   9 the DSI panel is attached, which is nonsense.
  10
  11 Signed-off-by: Jonathan Bell <jonathan@raspberrypi.org>
  12 ---
  13  drivers/gpu/drm/vc4/vc4_firmware_kms.c | 32 +++++++++++++++-----------
  14  1 file changed, 18 insertions(+), 14 deletions(-)
  15
  16 --- a/drivers/gpu/drm/vc4/vc4_firmware_kms.c
  17 +++ b/drivers/gpu/drm/vc4/vc4_firmware_kms.c
  18 @@ -1303,13 +1303,13 @@ static int vc4_fkms_bind(struct device *
  19                                     RPI_FIRMWARE_FRAMEBUFFER_GET_NUM_DISPLAYS,
  20                                     &num_displays, sizeof(u32));
  21
  22 -       /* If we fail to get the number of displays, or it returns 0, then
  23 +       /* If we fail to get the number of displays, then
  24          * assume old firmware that doesn't have the mailbox call, so just
  25          * set one display
  26          */
  27 -       if (ret || num_displays == 0) {
  28 +       if (ret) {
  29                 num_displays = 1;
  30 -               DRM_WARN("Unable to determine number of displays's. Assuming 1\n");
  31 +               DRM_WARN("Unable to determine number of displays - assuming 1\n");
  32                 ret = 0;
  33         }
  34
  35 @@ -1338,17 +1338,21 @@ static int vc4_fkms_bind(struct device *
  36                                   display_num);
  37         }
  38
  39 -       /* Map the SMI interrupt reg */
  40 -       crtc_list[0]->regs = vc4_ioremap_regs(pdev, 0);
  41 -       if (IS_ERR(crtc_list[0]->regs))
  42 -               DRM_ERROR("Oh dear, failed to map registers\n");
  43 -
  44 -       writel(0, crtc_list[0]->regs + SMICS);
  45 -       ret = devm_request_irq(dev, platform_get_irq(pdev, 0),
  46 -                              vc4_crtc_irq_handler, 0, "vc4 firmware kms",
  47 -                              crtc_list);
  48 -       if (ret)
  49 -               DRM_ERROR("Oh dear, failed to register IRQ\n");
  50 +       if (num_displays > 0) {
  51 +               /* Map the SMI interrupt reg */
  52 +               crtc_list[0]->regs = vc4_ioremap_regs(pdev, 0);
  53 +               if (IS_ERR(crtc_list[0]->regs))
  54 +                       DRM_ERROR("Oh dear, failed to map registers\n");
  55 +
  56 +               writel(0, crtc_list[0]->regs + SMICS);
  57 +               ret = devm_request_irq(dev, platform_get_irq(pdev, 0),
  58 +                                      vc4_crtc_irq_handler, 0,
  59 +                                      "vc4 firmware kms", crtc_list);
  60 +               if (ret)
  61 +                       DRM_ERROR("Oh dear, failed to register IRQ\n");
  62 +       } else {
  63 +               DRM_WARN("No displays found. Consider forcing hotplug if HDMI is attached\n");
  64 +       }
  65
  66         platform_set_drvdata(pdev, crtc_list);
  67