Commit b504f99c authored by Alvin Lee's avatar Alvin Lee Committed by Alex Deucher
Browse files

drm/amd/display: Enforce 60us prefetch for 200Mhz DCFCLK modes 



[Description]
- Due to bandwidth / arbitration issues at 200Mhz DCFCLK,
  we want to enforce minimum 60us of prefetch to avoid
  intermittent underflow issues
- Since 60us prefetch is already enforced for UCLK DPM0,
  and many DCFCLK's > 200Mhz are mapped to UCLK DPM1, in
  theory there should not be any UCLK DPM regressions by
  enforcing greater prefetch

Reviewed-by: default avatarNevenko Stupar <Nevenko.Stupar@amd.com>
Reviewed-by: default avatarJun Lei <Jun.Lei@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Acked-by: default avatarAlex Hung <alex.hung@amd.com>
Signed-off-by: default avatarAlvin Lee <Alvin.Lee2@amd.com>
Tested-by: default avatarDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent f57fa0f2

drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_32.c

+3 −2
Original line number Diff line number Diff line
@@ -810,7 +810,8 @@ static void DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerforman 
					v->SwathHeightY[k],

					v->SwathHeightC[k],

					TWait,

					v->DRAMSpeedPerState[mode_lib->vba.VoltageLevel] <= MEM_STROBE_FREQ_MHZ ?

					(v->DRAMSpeedPerState[mode_lib->vba.VoltageLevel] <= MEM_STROBE_FREQ_MHZ ||

						v->DCFCLKPerState[mode_lib->vba.VoltageLevel] <= MIN_DCFCLK_FREQ_MHZ) ?

							mode_lib->vba.ip.min_prefetch_in_strobe_us : 0,

					/* Output */

					&v->DSTXAfterScaler[k],
@@ -3310,7 +3311,7 @@ void dml32_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_l 
							v->swath_width_chroma_ub_this_state[k],

							v->SwathHeightYThisState[k],

							v->SwathHeightCThisState[k], v->TWait,

							v->DRAMSpeedPerState[i] <= MEM_STROBE_FREQ_MHZ ?

							(v->DRAMSpeedPerState[i] <= MEM_STROBE_FREQ_MHZ || v->DCFCLKState[i][j] <= MIN_DCFCLK_FREQ_MHZ) ?

									mode_lib->vba.ip.min_prefetch_in_strobe_us : 0,



							/* Output */

drivers/gpu/drm/amd/display/dc/dml/dcn32/display_mode_vba_32.h

+1 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ 
#define BPP_BLENDED_PIPE 0xffffffff



#define MEM_STROBE_FREQ_MHZ 1600

#define MIN_DCFCLK_FREQ_MHZ 200

#define MEM_STROBE_MAX_DELIVERY_TIME_US 60.0



struct display_mode_lib;