diff options
| -rw-r--r-- | Documentation/gpu/amdgpu-dc.rst | 6 | ||||
| -rw-r--r-- | drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 19 | ||||
| -rw-r--r-- | drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 30 |
3 files changed, 53 insertions, 2 deletions
diff --git a/Documentation/gpu/amdgpu-dc.rst b/Documentation/gpu/amdgpu-dc.rst index cc89b0fc11df..f7ff7e1309de 100644 --- a/Documentation/gpu/amdgpu-dc.rst +++ b/Documentation/gpu/amdgpu-dc.rst @@ -66,3 +66,9 @@ Display Core ============ **WIP** + +FreeSync Video +-------------- + +.. kernel-doc:: drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c + :doc: FreeSync Video diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c index c080ba15ae77..6f30c525caac 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c @@ -837,8 +837,23 @@ module_param_named(tmz, amdgpu_tmz, int, 0444); /** * DOC: freesync_video (uint) - * Enabled the optimization to adjust front porch timing to achieve seamless mode change experience - * when setting a freesync supported mode for which full modeset is not needed. + * Enable the optimization to adjust front porch timing to achieve seamless + * mode change experience when setting a freesync supported mode for which full + * modeset is not needed. + * + * The Display Core will add a set of modes derived from the base FreeSync + * video mode into the corresponding connector's mode list based on commonly + * used refresh rates and VRR range of the connected display, when users enable + * this feature. From the userspace perspective, they can see a seamless mode + * change experience when the change between different refresh rates under the + * same resolution. Additionally, userspace applications such as Video playback + * can read this modeset list and change the refresh rate based on the video + * frame rate. Finally, the userspace can also derive an appropriate mode for a + * particular refresh rate based on the FreeSync Mode and add it to the + * connector's mode list. + * + * Note: This is an experimental feature. + * * The default value: 0 (off). */ MODULE_PARM_DESC( 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) |