Am 12.11.21 um 15:30 schrieb Michel Dänzer:
On 2021-11-12 15:29, Michel Dänzer wrote:
On 2021-11-12 13:47, Christian König wrote:
Anyway this unfortunately turned out to be work for Harray and Nicholas. In
detail it's about this bug report here:
https://bugzilla.kernel.org/show_bug.cgi?id=214621
Lang was able to reproduce the issue and narrow it down to the pin in
amdgpu_display_crtc_page_flip_target().
In other words we somehow have an unbalanced pinning of the scanout buffer in
DC.
DC doesn't use amdgpu_display_crtc_page_flip_target AFAICT. The corresponding
pin with DC would be in dm_plane_helper_prepare_fb, paired with the unpin in
dm_plane_helper_cleanup_fb.
With non-DC, the pin in amdgpu_display_crtc_page_flip_target is paired with the
unpin in dm_plane_helper_cleanup_fb
This should say amdgpu_display_unpin_work_func.
Ah! So that is the classic (e.g. non atomic) path?
& dce_v*_crtc_disable. One thing I notice is that the pin is guarded by if
(!adev->enable_virtual_display), but the unpins seem unconditional. So could this
be about virtual display, and the problem is actually trying to unpin a BO that was
never pinned?
Nope, my educated guess is rather that we free up the BO before
amdgpu_display_unpin_work_func is called.
E.g. not pin unbalance, but rather use after free.
Regards,
Christian.
