drm/amd/display: don't call dm_pp_ function from an fpu block

Harry Wentland · alexdeucher · commit 59d3191f14dc · 2019-03-06T15:31:20.000-05:00
Powerplay functions called from dm_pp_* functions tend to do a
mutex_lock which isn't safe to do inside a kernel_fpu_begin/end block as
those will disable/enable preemption.

Rearrange the dm_pp_get_clock_levels_by_type_with_voltage calls to make
sure they happen outside of kernel_fpu_begin/end.

Cc: stable@vger.kernel.org
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
diff --git a/drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c b/drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c
@@ -1348,12 +1348,12 @@ void dcn_bw_update_from_pplib(struct dc *dc)
 	struct dm_pp_clock_levels_with_voltage fclks = {0}, dcfclks = {0};
 	bool res;
 
-	kernel_fpu_begin();
-
 	/* TODO: This is not the proper way to obtain fabric_and_dram_bandwidth, should be min(fclk, memclk) */
 	res = dm_pp_get_clock_levels_by_type_with_voltage(
 			ctx, DM_PP_CLOCK_TYPE_FCLK, &fclks);
 
+	kernel_fpu_begin();
+
 	if (res)
 		res = verify_clock_values(&fclks);
 
@@ -1372,9 +1372,13 @@ void dcn_bw_update_from_pplib(struct dc *dc)
 	} else
 		BREAK_TO_DEBUGGER();
 
+	kernel_fpu_end();
+
 	res = dm_pp_get_clock_levels_by_type_with_voltage(
 			ctx, DM_PP_CLOCK_TYPE_DCFCLK, &dcfclks);
 
+	kernel_fpu_begin();
+
 	if (res)
 		res = verify_clock_values(&dcfclks);
 
