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Robin Singh 19cc1f3829 drm/amd/display: fixed divide by zero kernel crash during dsc enablement
[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>
2021-04-20 21:36:41 -04:00
Documentation Merge drm/drm-fixes into drm-next 2021-04-13 23:15:09 +02:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
arch Merge drm/drm-fixes into drm-next 2021-04-13 23:15:09 +02:00
block block: remove the unused RQF_ALLOCED flag 2021-04-02 11:18:31 -06:00
certs certs: Replace K{U,G}IDT_INIT() with GLOBAL_ROOT_{U,G}ID 2021-01-21 16:16:10 +00:00
crypto crypto: mips/poly1305 - enable for all MIPS processors 2021-03-08 11:52:17 +01:00
drivers drm/amd/display: fixed divide by zero kernel crash during dsc enablement 2021-04-20 21:36:41 -04:00
fs for-5.12-rc6-tag 2021-04-11 11:53:36 -07:00
include Merge tag 'drm-msm-next-2021-04-11' of https://gitlab.freedesktop.org/drm/msm into drm-next 2021-04-13 23:35:54 +02:00
init Merge branch 'akpm' (patches from Andrew) 2021-03-14 12:23:34 -07:00
ipc fs: make helpers idmap mount aware 2021-01-24 14:27:20 +01:00
kernel Merge drm/drm-fixes into drm-next 2021-04-13 23:15:09 +02:00
lib Merge drm/drm-fixes into drm-next 2021-04-13 23:15:09 +02:00
mm Merge branch 'for-5.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu 2021-04-10 12:51:12 -07:00
net net: fix hangup on napi_disable for threaded napi 2021-04-09 12:50:31 -07:00
samples Merge git://git.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2021-03-09 17:15:56 -08:00
scripts Merge drm/drm-fixes into drm-next 2021-04-13 23:15:09 +02:00
security selinux/stable-5.12 PR 20210409 2021-04-09 11:51:06 -07:00
sound sound fixes for 5.12-rc7 2021-04-08 09:01:30 -07:00
tools perf tools fixes for v5.12: 3rd batch 2021-04-09 17:12:31 -07:00
usr Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
virt KVM: x86/mmu: Consider the hva in mmu_notifier retry 2021-02-22 13:16:53 -05:00
.clang-format cxl for 5.12 2021-02-24 09:38:36 -08:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore clang-lto series for v5.12-rc1 2021-02-23 09:28:51 -08:00
.mailmap .mailmap: fix old email addresses 2021-04-09 14:54:23 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS treewide: Miguel has moved 2021-02-26 09:41:03 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge drm/drm-fixes into drm-next 2021-04-13 23:15:09 +02:00
Makefile Linux 5.12-rc7 2021-04-11 15:16:13 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.