From: Robin Singh robin.singh@amd.com

[ Upstream commit 19cc1f3829567e7dca21c1389ea6407b8f5efab4 ]

[why] During dsc enable, a divide by zero condition triggered the kernel crash.

[how] An IGT test, which enable the DSC, was crashing at the time of restore the default dsc status, becaue of h_totals value becoming 0. So add a check before divide condition. If h_total is zero, gracefully ignore and set the default value.

kernel panic log:

[ 128.758827] divide error: 0000 [#1] PREEMPT SMP NOPTI [ 128.762714] CPU: 5 PID: 4562 Comm: amd_dp_dsc Tainted: G W 5.4.19-android-x86_64 #1 [ 128.769728] Hardware name: ADVANCED MICRO DEVICES, INC. Mauna/Mauna, BIOS WMN0B13N Nov 11 2020 [ 128.777695] RIP: 0010:hubp2_vready_at_or_After_vsync+0x37/0x7a [amdgpu] [ 128.785707] Code: 80 02 00 00 48 89 f3 48 8b 7f 08 b ...... [ 128.805696] RSP: 0018:ffffad8f82d43628 EFLAGS: 00010246 ...... [ 128.857707] CR2: 00007106d8465000 CR3: 0000000426530000 CR4: 0000000000140ee0 [ 128.865695] Call Trace: [ 128.869712] hubp3_setup+0x1f/0x7f [amdgpu] [ 128.873705] dcn20_update_dchubp_dpp+0xc8/0x54a [amdgpu] [ 128.877706] dcn20_program_front_end_for_ctx+0x31d/0x463 [amdgpu] [ 128.885706] dc_commit_state+0x3d2/0x658 [amdgpu] [ 128.889707] amdgpu_dm_atomic_commit_tail+0x4b3/0x1e7c [amdgpu] [ 128.897699] ? dm_read_reg_func+0x41/0xb5 [amdgpu] [ 128.901707] ? dm_read_reg_func+0x41/0xb5 [amdgpu] [ 128.905706] ? __is_insn_slot_addr+0x43/0x48 [ 128.909706] ? fill_plane_buffer_attributes+0x29e/0x3dc [amdgpu] [ 128.917705] ? dm_plane_helper_prepare_fb+0x255/0x284 [amdgpu] [ 128.921700] ? usleep_range+0x7c/0x7c [ 128.925705] ? preempt_count_sub+0xf/0x18 [ 128.929706] ? _raw_spin_unlock_irq+0x13/0x24 [ 128.933732] ? __wait_for_common+0x11e/0x18f [ 128.937705] ? _raw_spin_unlock_irq+0x13/0x24 [ 128.941706] ? __wait_for_common+0x11e/0x18f [ 128.945705] commit_tail+0x8b/0xd2 [drm_kms_helper] [ 128.949707] drm_atomic_helper_commit+0xd8/0xf5 [drm_kms_helper] [ 128.957706] amdgpu_dm_atomic_commit+0x337/0x360 [amdgpu] [ 128.961705] ? drm_atomic_check_only+0x543/0x68d [drm] [ 128.969705] ? drm_atomic_set_property+0x760/0x7af [drm] [ 128.973704] ? drm_mode_atomic_ioctl+0x6f3/0x85a [drm] [ 128.977705] drm_mode_atomic_ioctl+0x6f3/0x85a [drm] [ 128.985705] ? drm_atomic_set_property+0x7af/0x7af [drm] [ 128.989706] drm_ioctl_kernel+0x82/0xda [drm] [ 128.993706] drm_ioctl+0x225/0x319 [drm] [ 128.997707] ? drm_atomic_set_property+0x7af/0x7af [drm] [ 129.001706] ? preempt_count_sub+0xf/0x18 [ 129.005713] amdgpu_drm_ioctl+0x4b/0x76 [amdgpu] [ 129.009705] vfs_ioctl+0x1d/0x2a [ 129.013705] do_vfs_ioctl+0x419/0x43d [ 129.017707] ksys_ioctl+0x52/0x71 [ 129.021707] __x64_sys_ioctl+0x16/0x19 [ 129.025706] do_syscall_64+0x78/0x85 [ 129.029705] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Robin Singh robin.singh@amd.com Reviewed-by: Harry Wentland Harry.Wentland@amd.com Reviewed-by: Robin Singh Robin.Singh@amd.com Acked-by: Aurabindo Pillai aurabindo.pillai@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubp.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubp.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubp.c index bec7059f6d5d..a1318c31bcfa 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubp.c +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hubp.c @@ -1,5 +1,5 @@ /* - * Copyright 2012-17 Advanced Micro Devices, Inc. + * Copyright 2012-2021 Advanced Micro Devices, Inc. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), @@ -181,11 +181,14 @@ void hubp2_vready_at_or_After_vsync(struct hubp *hubp, else Set HUBP_VREADY_AT_OR_AFTER_VSYNC = 0 */ - if ((pipe_dest->vstartup_start - (pipe_dest->vready_offset+pipe_dest->vupdate_width - + pipe_dest->vupdate_offset) / pipe_dest->htotal) <= pipe_dest->vblank_end) { - value = 1; - } else - value = 0; + if (pipe_dest->htotal != 0) { + if ((pipe_dest->vstartup_start - (pipe_dest->vready_offset+pipe_dest->vupdate_width + + pipe_dest->vupdate_offset) / pipe_dest->htotal) <= pipe_dest->vblank_end) { + value = 1; + } else + value = 0; + } + REG_UPDATE(DCHUBP_CNTL, HUBP_VREADY_AT_OR_AFTER_VSYNC, value); }