diff options
| author | Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> | 2021-06-08 13:37:18 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2021-06-18 17:06:43 -0400 |
| commit | 5fd953a3f6e25859ad1633ccd9f6320f1067a46d (patch) | |
| tree | 397da23208b66332c9040e084694f1271fe73255 /drivers/gpu/drm/amd/display | |
| parent | 26c0504ad3e0fdee808dbf458dd31d7c12469ef9 (diff) | |
drm/amd/display: Add Freesync video documentation
Recently, we added support for an experimental feature named Freesync
video; for more details on that, refer to:
commit 6f59f229f8ed ("drm/amd/display: Skip modeset for front porch change")
commit d10cd527f5e5 ("drm/amd/display: Add freesync video modes based on preferred modes")
commit 0eb1af2e8205 ("drm/amd/display: Add module parameter for freesync video mode")
Nevertheless, we did not document it in detail in our driver. This
commit introduces a kernel-doc and expands the module parameter
description.
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Reviewed by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/amd/display')
| -rw-r--r-- | drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 30 |
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) |