diff options
| author | Fangzhi Zuo <Jerry.Zuo@amd.com> | 2025-09-18 16:25:45 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2025-11-18 11:52:18 -0500 |
| commit | cfa0904a35fd0231f4d05da0190f0a22ed881cce (patch) | |
| tree | a7b23178ad93c996f71b011c416de16ce7e0fa33 /drivers | |
| parent | 6a23ae0a96a600d1d12557add110e0bb6e32730c (diff) | |
drm/amd/display: Prevent Gating DTBCLK before It Is Properly Latched
[why]
1. With allow_0_dtb_clk enabled, the time required to latch DTBCLK to 600 MHz
depends on the SMU. If DTBCLK is not latched to 600 MHz before set_mode completes,
gating DTBCLK causes the DP2 sink to lose its clock source.
2. The existing DTBCLK gating sequence ungates DTBCLK based on both pix_clk and ref_dtbclk,
but gates DTBCLK when either pix_clk or ref_dtbclk is zero.
pix_clk can be zero outside the set_mode sequence before DTBCLK is properly latched,
which can lead to DTBCLK being gated by mistake.
[how]
Consider both pixel_clk and ref_dtbclk when determining when it is safe to gate DTBCLK;
this is more accurate.
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4701
Fixes: 5949e7c4890c ("drm/amd/display: Enable Dynamic DTBCLK Switch")
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit d04eb0c402780ca037b62a6aecf23b863545ebca)
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c | 4 | ||||
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c | 2 |
2 files changed, 4 insertions, 2 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c index b11383fba35f..1eb04772f5da 100644 --- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c +++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c @@ -394,6 +394,8 @@ void dcn35_update_clocks(struct clk_mgr *clk_mgr_base, display_count = dcn35_get_active_display_cnt_wa(dc, context, &all_active_disps); if (new_clocks->dtbclk_en && !new_clocks->ref_dtbclk_khz) new_clocks->ref_dtbclk_khz = 600000; + else if (!new_clocks->dtbclk_en && new_clocks->ref_dtbclk_khz > 590000) + new_clocks->ref_dtbclk_khz = 0; /* * if it is safe to lower, but we are already in the lower state, we don't have to do anything @@ -435,7 +437,7 @@ void dcn35_update_clocks(struct clk_mgr *clk_mgr_base, actual_dtbclk = REG_READ(CLK1_CLK4_CURRENT_CNT); - if (actual_dtbclk) { + if (actual_dtbclk > 590000) { clk_mgr_base->clks.ref_dtbclk_khz = new_clocks->ref_dtbclk_khz; clk_mgr_base->clks.dtbclk_en = new_clocks->dtbclk_en; } diff --git a/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c b/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c index de6d62401362..c899c09ea31b 100644 --- a/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c +++ b/drivers/gpu/drm/amd/display/dc/dccg/dcn35/dcn35_dccg.c @@ -1411,7 +1411,7 @@ static void dccg35_set_dtbclk_dto( __func__, params->otg_inst, params->pixclk_khz, params->ref_dtbclk_khz, req_dtbclk_khz, phase, modulo); - } else { + } else if (!params->ref_dtbclk_khz && !req_dtbclk_khz) { switch (params->otg_inst) { case 0: REG_UPDATE(DCCG_GATE_DISABLE_CNTL5, DTBCLK_P0_GATE_DISABLE, 0); |