Am 16.11.21 um 09:00 schrieb Lang Yu:
On Tue, Nov 16, 2021 at 08:14:08AM +0100, Christian KKKnig wrote:
Am 16.11.21 um 04:27 schrieb Lang Yu:
On Mon, Nov 15, 2021 at 01:04:15PM +0100, Michel DDDnzer wrote:
[SNIP]
Though a single call to dce_v*_0_crtc_do_set_base() will
only pin the BO, I found it will be unpinned in next call to
dce_v*_0_crtc_do_set_base().
Yeah, that's the normal case when the new BO is different from the old one.
To catch the case I described, try something like
diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
index 18a7b3bd633b..5726bd87a355 100644
--- a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
@@ -1926,6 +1926,7 @@ static int dce_v11_0_crtc_do_set_base(struct drm_crtc *crtc,
return r;
if (!atomic) {
+ WARN_ON_ONCE(target_fb == fb);
r = amdgpu_bo_pin(abo, AMDGPU_GEM_DOMAIN_VRAM);
if (unlikely(r != 0)) {
amdgpu_bo_unreserve(abo);
I did some tests, the warning can be triggered.
pin/unpin operations in *_crtc_do_set_base() and
amdgpu_display_crtc_page_flip_target() are mixed.
Ok sounds like we narrowed down the root cause pretty well.
Question is now how can we fix this? Just not pin the BO when target_fb ==
fb?
That worked. I did a few simple tests and didn't observe ttm_bo_release warnings
any more.
The pin/unpin logic,
1, fist crtc_mode_set, dce_v*_0_crtc_do_set_base() pins crtc->primary->fb(new),
old_fb is NULL.
2, second crtc_mode_set, dce_v*_0_crtc_do_set_base() pins crtc->primary->fb(new),
unpins old fb.
3, amdgpu_display_crtc_page_flip_target() pin/unpin operations.
4, third crtc_mode_set, dce_v*_0_crtc_do_set_base() pins crtc->primary->fb(new),
unpins old fb (it is pinned in last call to amdgpu_display_crtc_page_flip_target)
5, amdgpu_display_crtc_page_flip_target() pin/unpin operations.
.....
x, reboot, amdgpu_display_suspend_helper() is called, the last pinned fb was unpinned.
And I didn't observe amdgpu_bo_unpin() in dce_v*_0_crtc_disable() is called.
If the logic is wrong, please correct me.
I can't fully judge because I'm not that deep with my head in the old
display code, but from a ten mile high view it sounds sane to me. Michel
what do you think?
BTW: Nicholas are there any plans to get rid of all that stuff? It would
be a really nice cleanup of rather flaky code I think.
Thanks,
Christian.
Regards,
Lang
Thanks,
Christian.
Regards,
Lang
