On Mon, Mar 11, 2019 at 06:01:20PM -0300, Rodrigo Siqueira wrote:
> The function disable_outputs() and
> drm_atomic_helper_commit_modeset_enables() tries to retrieve
> helper_private from the target CRTC, for dereferencing some operations.
> However, the current implementation does not check whether
> helper_private is null and, if not, if it has a valid pointer to a dpms
> and commit functions. This commit adds pointer validations before
> trying to dereference the dpms and commit function.
>
> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiram...@gmail.com>
Please also adjust the kerneldoc for these functions. And I think the
patch subject can be improved, e.g. "Make ->atomic_enable/disable crtc
callbacks optional". Describe what you're trying to achieve in the
summary, not how you achieve it.
> ---
> drivers/gpu/drm/drm_atomic_helper.c | 30 ++++++++++++++++-------------
> 1 file changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c
> b/drivers/gpu/drm/drm_atomic_helper.c
> index 540a77a2ade9..fbeef7c461fc 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1028,14 +1028,16 @@ disable_outputs(struct drm_device *dev, struct
> drm_atomic_state *old_state)
>
>
> /* Right function depends upon target state. */
> - if (new_crtc_state->enable && funcs->prepare)
> - funcs->prepare(crtc);
> - else if (funcs->atomic_disable)
> - funcs->atomic_disable(crtc, old_crtc_state);
> - else if (funcs->disable)
> - funcs->disable(crtc);
> - else
> - funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
> + if (funcs) {
I don't think making funcs optional is a good idea. If you have a crtc
with no functions implemented, it's not terribly useful.
Also making functions optional just here is not going to help if we still
require it everywhere else.
-Daniel
> + if (new_crtc_state->enable && funcs->prepare)
> + funcs->prepare(crtc);
> + else if (funcs->atomic_disable)
> + funcs->atomic_disable(crtc, old_crtc_state);
> + else if (funcs->disable)
> + funcs->disable(crtc);
> + else if (funcs->dpms)
> + funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
> + }
>
> if (!(dev->irq_enabled && dev->num_crtcs))
> continue;
> @@ -1277,11 +1279,13 @@ void drm_atomic_helper_commit_modeset_enables(struct
> drm_device *dev,
> if (new_crtc_state->enable) {
> DRM_DEBUG_ATOMIC("enabling [CRTC:%d:%s]\n",
> crtc->base.id, crtc->name);
> -
> - if (funcs->atomic_enable)
> - funcs->atomic_enable(crtc, old_crtc_state);
> - else
> - funcs->commit(crtc);
> + if (funcs) {
> + if (funcs->atomic_enable)
> + funcs->atomic_enable(crtc,
> + old_crtc_state);
> + else if (funcs->atomic_enable)
> + funcs->commit(crtc);
> + }
> }
> }
>
> --
> 2.21.0
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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