2b3af27056
We recently improved our display atomic commit and tail sequence to
avoid some issues related to concurrency. One of the major changes
consisted of moving the interrupt disable and the stream release from
our atomic commit to our atomic tail (commit 6d90a208cfff
("drm/amd/display: Move disable interrupt into commit tail")) .
However, the new code introduced inside our commit tail function was
inserted right after the function
drm_atomic_helper_update_legacy_modeset_state(), which has routines for
updating internal data structs related to timestamps. As a result, in
certain conditions, the display module can reach a situation where we
update our constants and, after that, clean it. This situation generates
the following warning:
amdgpu 0000:03:00.0: drm_WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev))
WARNING: CPU: 6 PID: 1269 at drivers/gpu/drm/drm_vblank.c:722
drm_crtc_vblank_helper_get_vblank_timestamp_internal+0x32b/0x340 [drm]
...
RIP:
0010:drm_crtc_vblank_helper_get_vblank_timestamp_internal+0x32b/0x340
[drm]
...
Call Trace:
? dc_stream_get_vblank_counter+0x57/0x60 [amdgpu]
drm_crtc_vblank_helper_get_vblank_timestamp+0x1c/0x20 [drm]
drm_get_last_vbltimestamp+0xad/0xc0 [drm]
drm_reset_vblank_timestamp+0x63/0xd0 [drm]
drm_crtc_vblank_on+0x85/0x150 [drm]
amdgpu_dm_atomic_commit_tail+0xaf1/0x2330 [amdgpu]
commit_tail+0x99/0x130 [drm_kms_helper]
drm_atomic_helper_commit+0x123/0x150 [drm_kms_helper]
amdgpu_dm_atomic_commit+0x11/0x20 [amdgpu]
drm_atomic_commit+0x4a/0x50 [drm]
drm_atomic_helper_set_config+0x7c/0xc0 [drm_kms_helper]
drm_mode_setcrtc+0x20b/0x7e0 [drm]
? tomoyo_path_number_perm+0x6f/0x200
? drm_mode_getcrtc+0x190/0x190 [drm]
drm_ioctl_kernel+0xae/0xf0 [drm]
drm_ioctl+0x245/0x400 [drm]
? drm_mode_getcrtc+0x190/0x190 [drm]
amdgpu_drm_ioctl+0x4e/0x80 [amdgpu]
__x64_sys_ioctl+0x91/0xc0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
...
For fixing this issue we rely upon a refactor introduced on
drm_atomic_helper_update_legacy_modeset_state ("Remove the timestamping
constant update from drm_atomic_helper_update_legacy_modeset_state()")
which decouples constant values update from
drm_atomic_helper_update_legacy_modeset_state to a new helper.
Basically, this commit uses this new helper and place it right after our
release module to avoid a situation where our CRTC struct gets wrong
values.
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1373
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1349
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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.