On Thu, 2026-03-26 at 10:57 +0800, ChuanYu Tseng wrote:
> FPU guards (DC_FP_START/DC_FP_END) are required to wrap around code that
> can manipulates floats. To do this properly, the FPU guards must be used
> in a file that is not compiled as a FPU unit. If the guards are used in
> a file that is a FPU unit, other sections in the file that aren't guarded
> may be end up being compiled to use FPU operations.
/* snip */
> diff --git a/drivers/gpu/drm/amd/display/dc/dml2_0/dml2_wrapper.c
> b/drivers/gpu/drm/amd/display/dc/dml2_0/dml2_wrapper.c
We have:
CFLAGS_$(AMDDALPATH)/dc/dml2_0/dml2_wrapper.o := $(dml2_rcflags)
and
dml2_rcflags := $(CC_FLAGS_NO_FPU)
so this file isn't compiled as a FPU unit. Why removing the guards
here?
/* snip */
> index 408559d6fb2d..f8250c80be02 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml2_0/dml2_wrapper.c
> +++ b/drivers/gpu/drm/amd/display/dc/dml2_0/dml2_wrapper.c
> @@ -6,7 +6,20 @@
> */
>
> #include "dml2_internal_types.h"
> +#include "dml2_wrapper.h"
> #include "dml2_wrapper_fpu.h"
> +#include "dml21_wrapper.h"
> +#include "dml21_wrapper_fpu.h"
> +
> +#include "dc_fpu.h"
> +
> +struct dml2_context *dml2_allocate_memory(void)
> +{
> + struct dml2_context *dml2;
> +
> + DC_RUN_WITH_PREEMPTION_ENABLED(dml2 = vzalloc(sizeof(struct
> dml2_context)));
> + return dml2;
> +}
>
> bool dml2_validate(const struct dc *in_dc, struct dc_state *context, struct
> dml2_context *dml2,
> enum dc_validate_mode validate_mode)
> @@ -23,16 +36,12 @@ bool dml2_validate(const struct dc *in_dc, struct
> dc_state *context, struct dml2
> return out;
> }
>
> - DC_FP_START();
Notably the removal of this is causing:
[ 3.943927] do_fpu invoked from kernel context![#1]:
[ 3.948860] CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted
7.0.3-aosc-main-4k #2 PREEMPT(lazy)
[ 3.957938] Hardware name: Loongson
Loongson-3B6000x1-7A2000x1-XB612B0_v1.1/XB612B0_v1.1, BIOS
Loongson-FwSdk-V5.0.0431-stable202602 04/10/26 09:20:09
[ 3.971334] Workqueue: sync_wq local_pci_probe_callback
[ 3.976528] pc ffff800002becd80 ra ffff800002becd30 tp 90000001005d8000 sp
90000001005db5e0
[ 3.984827] a0 ffff80001326ebf8 a1 0000000000000000 a2 ffff80001326ec98 a3
ffff80001326ec90
[ 3.993124] a4 ffff80001326ec90 a5 0000000000000000 a6 0000000000000000 a7
0000000000000000
[ 4.001422] t0 ffff800003327000 t1 ffff80001326f000 t2 0000000000000001 t3
0000000000000000
[ 4.009720] t4 0000000000000004 t5 0000000000000100 t6 0000000000000000 t7
0000000000000000
[ 4.018018] t8 0000000000000000 u0 ffff800002be8220 s9 90000001413e2000 s0
9000000160c00000
[ 4.026316] s1 9000000161c80000 s2 9000000160c00000 s3 90000001223af080 s4
9000000161c80000
[ 4.034613] s5 9000000160c00000 s6 9000000161c80000 s7 9000000161c40000 s8
ffff80001326a000
[ 4.042912] ra: ffff800002becd30
dml21_map_dc_state_into_dml_display_cfg+0x40/0x12a0 [amdgpu]
[ 4.052169] ERA: ffff800002becd80
dml21_map_dc_state_into_dml_display_cfg+0x90/0x12a0 [amdgpu]
[ 4.061277] CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
[ 4.067423] PRMD: 00000004 (PPLV0 +PIE -PWE)
[ 4.071749] EUEN: 00000000 (-FPE -SXE -ASXE -BTE)
[ 4.076508] ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
[ 4.081266] ESTAT: 000f0000 [FPD] (IS= ECode=15 EsubCode=0)
[ 4.086801] PRID: 0014d011 (Loongson-64bit, Loongson-3B6000)
[ 4.092507] Modules linked in: amdgpu(+) hid_logitech_dj i2c_algo_bit
drm_ttm_helper ttm drm_exec drm_suballoc_helper drm_buddy
drm_panel_backlight_quirks gpu_sched amdxcp drm_display_helper cec hid_generic
pwm_loongson la_ow_syscall
ntsync i2c_dev dmi_sysfs
[ 4.115253] Process kworker/0:1 (pid: 11, threadinfo=00000000187c43c8,
task=00000000627a7089)
[ 4.123725] Stack : ffff8000135e6360 ffff8000135e66b8 0000000000000000
0000043800000780
[ 4.131681] ffff800003328000 9000000161c40000 9000000161c802d8
ffff800002c32b28
[ 4.139637] ffff8000135e63f0 0000000000000000 0000000000000000
0000000000000000
[ 4.147592] 0000000000000000 0000000000000000 0000000000000000
9000000121846010
[ 4.155548] 0000000000000000 9000000161c80000 9000000161c80000
0000000000000001
[ 4.163504] 0000000000000001 90000001223af080 9000000160c00000
ffff80001326a000
[ 4.171460] ffff80001326a000 ffff800002bef274 9000000161c86000
0000000000000001
[ 4.179415] 0000000000000010 0000000000000001 9000000161c80000
ffff800002aeb330
[ 4.187371] 9000000160c00000 9000000160c00000 90000001413e2000
90000001223af080
[ 4.195326] 0000000000000010 0000000000000001 90000001415b0000
ffff800002851348
[ 4.203282] ...
[ 4.205705] Call Trace:
[ 4.205707] [<ffff800002becd80>]
dml21_map_dc_state_into_dml_display_cfg+0x90/0x12a0 [amdgpu]
[ 4.216978] [<ffff800002bef270>] dml21_validate+0xc0/0x160 [amdgpu]
[ 4.223573] [<ffff800002aeb32c>] dcn401_validate_bandwidth+0xdc/0x290
[amdgpu]
[ 4.231156] [<ffff800002851344>] create_validate_stream_for_sink+0x574/0x5b0
[amdgpu]
[ 4.239328] [<ffff800002851404>] amdgpu_dm_connector_mode_valid+0x84/0x2c0
[amdgpu]
[ 4.247312] [<9000000006bc2db4>] drm_connector_mode_valid+0x44/0xc0
[ 4.253542] [<9000000006bc2f6c>] __drm_helper_update_and_validate+0x13c/0x490
[ 4.260632] [<9000000006bc35c8>]
drm_helper_probe_single_connector_modes+0x308/0x6c0
[ 4.268326] [<9000000006ba055c>] drm_client_modeset_probe+0x1bc/0x1a50
[ 4.274811] [<9000000006bc5df8>]
__drm_fb_helper_initial_config_and_unlock+0x38/0x6f0
[ 4.282594] [<9000000006bccfcc>] drm_fbdev_client_hotplug+0x9c/0x120
[ 4.288906] [<9000000006b9ddd0>] drm_client_register+0x60/0xb0
[ 4.294702] [<9000000006bcd158>] drm_fbdev_client_setup+0xa8/0x260
[ 4.300841] [<9000000006bcbed8>] drm_client_setup+0xf8/0x170
[ 4.306461] [<ffff80000236a35c>] amdgpu_pci_probe+0x38c/0x8a0 [amdgpu]
[ 4.313291] [<9000000006957294>] local_pci_probe+0x44/0xe0
[ 4.318740] [<900000000695734c>] local_pci_probe_callback+0x1c/0x40
[ 4.324965] [<9000000005a6d4f8>] process_one_work+0x1a8/0x670
[ 4.330672] [<9000000005a6e42c>] worker_thread+0x1cc/0x3a0
[ 4.336120] [<9000000005a787d4>] kthread+0x134/0x170
[ 4.341049] [<90000000074a8314>] ret_from_kernel_thread+0x24/0x1d0
[ 4.347191] [<90000000059e28c4>] ret_from_kernel_thread_asm+0xc/0x88
[ 4.353504]
[ 4.354975] Code: 40074580 1a00e76c 29c2207d <2bc1a078> 1400003d 2b926198
038b03bd 00150369 29c30076
[ 4.364664]
[ 4.366156] ---[ end trace 0000000000000000 ]---
Reported-by: xinmu <[email protected]>
--
Xi Ruoyao <[email protected]>
