From: Sung Lee <sung.lee@xxxxxxx>
[WHY]
SMU FW previously had an issue with lowering display clock to below 100
MHz, and a workaround was put in to limit it. Newest SMU FW does not
have this issue, and no longer needs the 100MHz cap.
[HOW]
Remove the 100MHz cap based on the SMU FW version.
Signed-off-by: Sung Lee <sung.lee@xxxxxxx>
Reviewed-by: Yongqiang Sun <yongqiang.sun@xxxxxxx>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
index 64cbd5462c79..ab267ddd4abe 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
@@ -46,6 +46,7 @@
/* Constants */
#define LPDDR_MEM_RETRAIN_LATENCY 4.977 /* Number obtained from LPDDR4 Training Counter Requirement doc */
+#define SMU_VER_55_51_0 0x373300 /* SMU Version that is able to set DISPCLK below 100MHz */
/* Macros */
@@ -720,6 +721,13 @@ void rn_clk_mgr_construct(
} else {
struct clk_log_info log_info = {0};
+ clk_mgr->smu_ver = rn_vbios_smu_get_smu_version(clk_mgr);
+
+ /* SMU Version 55.51.0 and up no longer have an issue
+ * that needs to limit minimum dispclk */
+ if (clk_mgr->smu_ver >= SMU_VER_55_51_0)
+ debug->min_disp_clk_khz = 0;
+
/* TODO: Check we get what we expect during bringup */
clk_mgr->base.dentist_vco_freq_khz = get_vco_frequency_from_reg(clk_mgr);
--
2.25.1
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