drm/msm: Sanitize the modeset_is_locked checks in dpu (ab198a7a) · Commits · 戴 / test

As Daniel mentions in his email [1], non-blocking commits don't hold the modeset locks, so we can safely access state as long as these functions are in the commit path. So remove the WARN_ON in dpu_kms_encoder_enable. In dpu_crtc_get_intf_mode, things are a bit more complicated. So keep the WARN_ON, but add a comment explaining the situation and hope someone comes along and fixes the issue. [1]- https://lists.freedesktop.org/archives/dri-devel/2019-October/239441.html Link to v1: https://patchwork.freedesktop.org/patch/msgid/20191010151351.126735-1-sean@poorly.run Changes in v2: - Restored the WARN_ON in get_intf_mode and added a clarifying comment (Daniel) Fixes: ("drm/msm: dpu: Add modeset lock checks where applicable") Cc: Jeykumar Sankaran <jsanka@codeaurora.org> Cc: Rob Clark <robdclark@chromium.org> Suggested-by:

Daniel Vetter <daniel@ffwll.ch> Reviewed-by:

Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by:

Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20191010181801.186069-1-sean@poorly.run

drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -271,6 +271,15 @@ enum dpu_intf_mode dpu_crtc_get_intf_mode(struct drm_crtc *crtc)
		return INTF_MODE_NONE;
		}

		/*
		* TODO: This function is called from dpu debugfs and as part of atomic
		* check. When called from debugfs, the crtc->mutex must be held to
		* read crtc->state. However reading crtc->state from atomic check isn't
		* allowed (unless you have a good reason, a big comment, and a deep
		* understanding of how the atomic/modeset locks work (<- and this is
		* probably not possible)). So we'll keep the WARN_ON here for now, but
		* really we need to figure out a better way to track our operating mode
		*/
		WARN_ON(!drm_modeset_is_locked(&crtc->mutex));

		/* TODO: Returns the first INTF_MODE, could there be multiple values? */

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -316,7 +316,6 @@ void dpu_kms_encoder_enable(struct drm_encoder *encoder)
		if (funcs && funcs->commit)
		funcs->commit(encoder);

		WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
		drm_for_each_crtc(crtc, dev) {
		if (!(crtc->state->encoder_mask & drm_encoder_mask(encoder)))
		continue;

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