From: Nicholas Kazlauskas nicholas.kazlauskas@amd.com
[ Upstream commit 30f90f3c1c2c63c2fa44f61233737d27b72637c2 ]
[Why] Hardware implements root clock gating by utilizing the DPP DTO registers with a special case of DTO enabled, phase = 0, modulo = 1. This conflicts with our policy to always update the DPPDTO for cases where it's expected to be disabled.
The pipes unexpectedly enter a higher power state than expected because of this programming flow.
[How] Guard the upper layers of HWSS against this hardware quirk with programming the register with an internal state flag in DCCG.
While technically acting as global state for the DCCG, HWSS shouldn't be expected to understand the hardware quirk for having DTO disabled causing more power than DTO enabled with this specific setting.
This also prevents sequencing errors from occuring in the future if we have to program DPP DTO in multiple locations.
Acked-by: Stylon Wang stylon.wang@amd.com Signed-off-by: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Reviewed-by: Jun Lei jun.lei@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dccg.c | 8 ++++++++ drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c | 5 +++++ drivers/gpu/drm/amd/display/dc/inc/hw/dccg.h | 1 + 3 files changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dccg.c b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dccg.c index 7d2b982506fd7..cef32a1f91cdc 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dccg.c +++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_dccg.c @@ -47,6 +47,14 @@ void dccg31_update_dpp_dto(struct dccg *dccg, int dpp_inst, int req_dppclk) { struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
+ if (dccg->dpp_clock_gated[dpp_inst]) { + /* + * Do not update the DPPCLK DTO if the clock is stopped. + * It is treated the same as if the pipe itself were in PG. + */ + return; + } + if (dccg->ref_dppclk && req_dppclk) { int ref_dppclk = dccg->ref_dppclk; int modulo, phase; diff --git a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c index 85ea3334355c2..97c6a79dfba66 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c +++ b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c @@ -296,6 +296,9 @@ static void dccg314_dpp_root_clock_control( { struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
+ if (dccg->dpp_clock_gated[dpp_inst] == clock_on) + return; + if (clock_on) { /* turn off the DTO and leave phase/modulo at max */ REG_UPDATE(DPPCLK_DTO_CTRL, DPPCLK_DTO_ENABLE[dpp_inst], 0); @@ -309,6 +312,8 @@ static void dccg314_dpp_root_clock_control( DPPCLK0_DTO_PHASE, 0, DPPCLK0_DTO_MODULO, 1); } + + dccg->dpp_clock_gated[dpp_inst] = !clock_on; }
static const struct dccg_funcs dccg314_funcs = { diff --git a/drivers/gpu/drm/amd/display/dc/inc/hw/dccg.h b/drivers/gpu/drm/amd/display/dc/inc/hw/dccg.h index ad6acd1b34e1d..9651cccb084a3 100644 --- a/drivers/gpu/drm/amd/display/dc/inc/hw/dccg.h +++ b/drivers/gpu/drm/amd/display/dc/inc/hw/dccg.h @@ -68,6 +68,7 @@ struct dccg { const struct dccg_funcs *funcs; int pipe_dppclk_khz[MAX_PIPES]; int ref_dppclk; + bool dpp_clock_gated[MAX_PIPES]; //int dtbclk_khz[MAX_PIPES];/* TODO needs to be removed */ //int audio_dtbclk_khz;/* TODO needs to be removed */ //int ref_dtbclk_khz;/* TODO needs to be removed */