[PATCH] drm: add logging for RMFB ioctl

[PATCH] drm: add logging for RMFB ioctl

[Simon Ser]

We already have logging for ADDFB2. Add some logging for RMFB as
well.

This can be handy when trying to find out why a CRTC gets magically
disabled.

Signed-off-by: Simon Ser <contact@emersion.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/drm_framebuffer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index 4d01464b6f95..da77ceeb35e3 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -404,6 +404,7 @@ static void drm_mode_rmfb_work_fn(struct work_struct *w)
 		struct drm_framebuffer *fb =
 			list_first_entry(&arg->fbs, typeof(*fb), filp_head);
 
+		drm_dbg_kms(fb->dev, "Removing [FB:%d]\n", fb->base.id);
 		list_del_init(&fb->filp_head);
 		drm_framebuffer_remove(fb);
 	}
-- 
2.32.0

Re: [PATCH] drm: add logging for RMFB ioctl

[Daniel Vetter]

On Fri, Jul 23, 2021 at 5:46 PM Simon Ser <contact@emersion.fr> wrote:
>
> We already have logging for ADDFB2. Add some logging for RMFB as
> well.
>
> This can be handy when trying to find out why a CRTC gets magically
> disabled.
>
> Signed-off-by: Simon Ser <contact@emersion.fr>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_framebuffer.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
> index 4d01464b6f95..da77ceeb35e3 100644
> --- a/drivers/gpu/drm/drm_framebuffer.c
> +++ b/drivers/gpu/drm/drm_framebuffer.c
> @@ -404,6 +404,7 @@ static void drm_mode_rmfb_work_fn(struct work_struct *w)
>                 struct drm_framebuffer *fb =
>                         list_first_entry(&arg->fbs, typeof(*fb), filp_head);
>
> +               drm_dbg_kms(fb->dev, "Removing [FB:%d]\n", fb->base.id);

I'd hammer more in what happens and why this happens. Maybe something like this?

"Disabling [FB:¯from all active usage due to RMFB IOCTL\n"

Also I wonder whether we could put some additional debug output into
drm_framebuffer_remove when we either disable just the plane or the
entire crtc as further clue. Like

"Disabling CRTC|PLANE because FB is being removed from all active use\n"

Also, because you're this great at typing docs: Kerneldoc for RMFB
would be nice, but there's not even a struct to attach it to :-/ Any
ideas for how to do that?
-Daniel

>                 list_del_init(&fb->filp_head);
>                 drm_framebuffer_remove(fb);
>         }
> --
> 2.32.0
>
>


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch