[PATCH 5.0 223/238] drm/amd/display: dont call dm_pp_ function from an fpu block

From: Greg Kroah-Hartman
Date: Fri Mar 22 2019 - 08:23:47 EST


5.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Harry Wentland <harry.wentland@xxxxxxx>

commit 59d3191f14dc18881fec1172c7096b7863622803 upstream.

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@xxxxxxxxxxxxxxx
Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Harry Wentland <harry.wentland@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c
+++ b/drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c
@@ -1355,12 +1355,12 @@ void dcn_bw_update_from_pplib(struct 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);

@@ -1379,9 +1379,13 @@ void dcn_bw_update_from_pplib(struct 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);