drm/amdgpu: add some comments in DCE6

Add some comments.

Signed-off-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
index 5c3f96630c1018d2eec6f9bfccf369805bdeec01..ba9ccfba2959dc3cfa30f86683fc8dcfd6815ab9 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
@@ -206,9 +206,9 @@ static void dce_v6_0_page_flip(struct amdgpu_device *adev,
        /* update the scanout addresses */
        WREG32(mmGRPH_PRIMARY_SURFACE_ADDRESS_HIGH + amdgpu_crtc->crtc_offset,
               upper_32_bits(crtc_base));
+       /* writing to the low address triggers the update */
        WREG32(mmGRPH_PRIMARY_SURFACE_ADDRESS + amdgpu_crtc->crtc_offset,
               (u32)crtc_base);
-
        /* post the write */
        RREG32(mmGRPH_PRIMARY_SURFACE_ADDRESS + amdgpu_crtc->crtc_offset);
 }
@@ -218,11 +218,11 @@ static int dce_v6_0_crtc_get_scanoutpos(struct amdgpu_device *adev, int crtc,
 {
        if ((crtc < 0) || (crtc >= adev->mode_info.num_crtc))
                return -EINVAL;
+
        *vbl = RREG32(mmCRTC_V_BLANK_START_END + crtc_offsets[crtc]);
        *position = RREG32(mmCRTC_STATUS_POSITION + crtc_offsets[crtc]);
 
        return 0;
-
 }
 
 /**
@@ -1006,6 +1006,18 @@ static void dce_v6_0_program_watermarks(struct amdgpu_device *adev,
 }
 
 /* watermark setup */
+/**
+ * dce_v6_0_line_buffer_adjust - Set up the line buffer
+ *
+ * @adev: amdgpu_device pointer
+ * @amdgpu_crtc: the selected display controller
+ * @mode: the current display mode on the selected display
+ * controller
+ *
+ * Setup up the line buffer allocation for
+ * the selected display controller (CIK).
+ * Returns the line buffer size in pixels.
+ */
 static u32 dce_v6_0_line_buffer_adjust(struct amdgpu_device *adev,
                                   struct amdgpu_crtc *amdgpu_crtc,
                                   struct drm_display_mode *mode,
@@ -1386,6 +1398,8 @@ static int dce_v6_0_audio_init(struct amdgpu_device *adev)
                adev->mode_info.audio.pin[i].connected = false;
                adev->mode_info.audio.pin[i].offset = pin_offsets[i];
                adev->mode_info.audio.pin[i].id = i;
+               /* disable audio.  it will be set up later */
+               /* XXX remove once we switch to ip funcs */
                dce_v6_0_audio_enable(adev, &adev->mode_info.audio.pin[i], false);
        }