It should be noted that FAMS is an additional feature to enable mclk switching in more marginal cases than would normally be possible. Alex On Mon, Jun 13, 2022 at 9:32 AM Vanzylldejong, Harry <Harry.Vanzylldejong@xxxxxxx> wrote: > > [AMD Official Use Only - General] > > Hi Chandan, > > When using Firmware Assisted Memory clock Switching (FAMS), when the memory clock is switched the frame rate is dropped for at least 1 frame, > sometimes 2-3 frames to make the V-Blank long enough to handle the period where the GDDR6 memory is unavailable when the memory clock switches. > This drop may be noticeable by gamers, especially if the memory clock wants to change it's clock rate several times a second, > which is what we observed just on the desktop. > To guarantee best game performance, we disable FAMS during game play. > > Harry > > > -----Original Message----- > From: VURDIGERENATARAJ, CHANDAN <CHANDAN.VURDIGERENATARAJ@xxxxxxx> > Sent: June 13, 2022 8:42 AM > To: Michel Dänzer <michel.daenzer@xxxxxxxxxxx>; Mahfooz, Hamza <Hamza.Mahfooz@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx > Cc: Wang, Chao-kai (Stylon) <Stylon.Wang@xxxxxxx>; Liu, HaoPing (Alan) <HaoPing.Liu@xxxxxxx>; Li, Sun peng (Leo) <Sunpeng.Li@xxxxxxx>; Lakha, Bhawanpreet <Bhawanpreet.Lakha@xxxxxxx>; Zhuo, Qingqing (Lillian) <Qingqing.Zhuo@xxxxxxx>; Siqueira, Rodrigo <Rodrigo.Siqueira@xxxxxxx>; Li, Roman <Roman.Li@xxxxxxx>; Chiu, Solomon <Solomon.Chiu@xxxxxxx>; Zuo, Jerry <Jerry.Zuo@xxxxxxx>; Pillai, Aurabindo <Aurabindo.Pillai@xxxxxxx>; Vanzylldejong, Harry <Harry.Vanzylldejong@xxxxxxx>; Lin, Wayne <Wayne.Lin@xxxxxxx>; Wentland, Harry <Harry.Wentland@xxxxxxx>; Gutierrez, Agustin <Agustin.Gutierrez@xxxxxxx>; Kotarac, Pavle <Pavle.Kotarac@xxxxxxx> > Subject: RE: [PATCH 20/23] drm/amd/display: Disables dynamic memory clock switching in games > > Hi, > > Can you please elaborate on why dynamic memory clock switching can affect Game performance? > > BR, > Chandan V N > > > >On 2022-06-10 22:52, Hamza Mahfooz wrote: > >> From: Harry VanZyllDeJong <harry.vanzylldejong@xxxxxxx> > >> > >> [WHY] > >> Game performace may be affected if dynamic memory clock switching is > >> enabled while playing games. > >> > >> [HOW] > >> Propagate the vrr active state to dirty bit so that on mode set it > >> disables dynamic memory clock switching. > > > >So dynamic memory clock switching will be disabled whenever VRR is enabled? > > > >Note that there is ongoing discussion about how Wayland compositors could usefully keep VRR enabled all the time, as opposed to only while >there's a fullscreen application like a game. So "VRR is enabled" likely won't be equivalent to "game is running" in the long term. > > > > > -- > Earthling Michel Dänzer | https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fredhat.com%2F&data=05%7C01%7Cchandan.vurdigerenataraj%40amd.com%7C005764271a144b5832c408da4d293dee%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637907136793233201%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=NSiOtjfwkelxkZMRFLzFs1mFPvosOFZnqrcNvRb9J6E%3D&reserved=0 > Libre software enthusiast | Mesa and Xwayland developer
