On Wed, May 25, 2016 at 12:51 PM, Lukas Wunner lukas@wunner.de wrote:
On Tue, May 24, 2016 at 11:30:42PM +0200, Daniel Vetter wrote:
On Tue, May 24, 2016 at 06:03:27PM +0200, Lukas Wunner wrote:
When a drm_crtc structure is destroyed with drm_crtc_cleanup(), the DRM core does not turn off the crtc first and neither do the drivers. With nouveau, radeon and amdgpu, this causes a runtime pm ref to be leaked on driver unload if at least one crtc was enabled.
(See usage of have_disp_power_ref in nouveau_crtc_set_config(), radeon_crtc_set_config() and amdgpu_crtc_set_config()).
Fixes: 5addcf0a5f0f ("nouveau: add runtime PM support (v0.9)") Cc: Dave Airlie airlied@redhat.com Tested-by: Karol Herbst nouveau@karolherbst.de Signed-off-by: Lukas Wunner lukas@wunner.de
This is a core regression, we fixed it again. Previously when unreference drm_planes the core made sure that it's not longer in use, which had the side effect of shutting everything off in module unload.
For a bunch of reasons we've stopped doing that, but that turned out to be a mistake. It's fixed since
commit f2d580b9a8149735cbc4b59c4a8df60173658140 Author: Maarten Lankhorst maarten.lankhorst@linux.intel.com Date: Wed May 4 14:38:26 2016 +0200
drm/core: Do not preserve framebuffer on rmfb, v4.Your patch shouldn't be needed with that any more. If it still is it's most likely the fbdev cleanup done too late, but you /should/ get a big WARNING splat in that case from drm_mode_config_cleanup().
I tested it and at least with nouveau, the above-mentioned commit does *not* solve the issue, so patch [9/9] of this series is still needed. I do not get a WARN splat when unloading nouveau.
With legacy kms the only way to keep a crtc enabled is to display a drm_framebuffer on it. And drm_mode_config_cleanup has a WARN_ON if framebuffers are left behind. There's a bunch of options: - nouveau somehow manages to keep the crtc on without a framebuffer - nouveau somehow leaks a drm_framebuffer, but removes it from the fb_list - something else
There's still no need to forcefully shut down crtc at cleanup time in the core, this is still a driver bug. So yes your patch might be needed, but it's not the right fix. -Daniel