bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-30 20:42:33 -04:00
Code Issues Packages Projects Releases Wiki Activity

drm/amd/display: Add Freesync video documentation

Browse Source 
Recently, we added support for an experimental feature named Freesync
video; for more details on that, refer to:

commit 6f59f229f8 ("drm/amd/display: Skip modeset for front porch change")
commit d10cd527f5 ("drm/amd/display: Add freesync video modes based on preferred modes")
commit 0eb1af2e82 ("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>
This commit is contained in:
Rodrigo Siqueira
2021-06-08 13:37:18 -04:00
committed by Alex Deucher
parent 26c0504ad3
commit 5fd953a3f6
3 changed files with 53 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
View File

@@ -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)