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Diffstat (limited to 'drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c')
-rw-r--r--drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 10f878910e55..26f0ebdb38a9 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -5646,6 +5646,36 @@ static void apply_dsc_policy_for_stream(struct amdgpu_dm_connector *aconnector,
}
#endif
+/**
+ * DOC: FreeSync Video
+ *
+ * When a userspace application wants to play a video, the content follows a
+ * standard format definition that usually specifies the FPS for that format.
+ * The below list illustrates some video format and the expected FPS,
+ * respectively:
+ *
+ * - TV/NTSC (23.976 FPS)
+ * - Cinema (24 FPS)
+ * - TV/PAL (25 FPS)
+ * - TV/NTSC (29.97 FPS)
+ * - TV/NTSC (30 FPS)
+ * - Cinema HFR (48 FPS)
+ * - TV/PAL (50 FPS)
+ * - Commonly used (60 FPS)
+ * - Multiples of 24 (48,72,96 FPS)
+ *
+ * The list of standards video format is not huge and can be added to the
+ * connector modeset list beforehand. With that, userspace can leverage
+ * FreeSync to extends the front porch in order to attain the target refresh
+ * rate. Such a switch will happen seamlessly, without screen blanking or
+ * reprogramming of the output in any other way. If the userspace requests a
+ * modesetting change compatible with FreeSync modes that only differ in the
+ * refresh rate, DC will skip the full update and avoid blink during the
+ * transition. For example, the video player can change the modesetting from
+ * 60Hz to 30Hz for playing TV/NTSC content when it goes full screen without
+ * causing any display blink. This same concept can be applied to a mode
+ * setting change.
+ */
static struct drm_display_mode *
get_highest_refresh_rate_mode(struct amdgpu_dm_connector *aconnector,
bool use_probed_modes)