| Message ID | 20191010181801.186069-1-sean@poorly.run (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ab198a7aab65d6fcdbde082ff59a790dbf7e08f4 |
| Headers | show |
| Series | [v2] drm/msm: Sanitize the modeset_is_locked checks in dpu | expand |
On Thu, Oct 10, 2019 at 02:17:44PM -0400, Sean Paul wrote: > From: Sean Paul <seanpaul@chromium.org> > > 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: 1dfdb0e107db ("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> > Partially-Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Applied to msm-next with danvet's full irc r-b, thanks for the report and review! Sean > Signed-off-by: Sean Paul <seanpaul@chromium.org> > --- > drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 9 +++++++++ > drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 1 - > 2 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c > index 0b9dc042d2e22..f197dce545761 100644 > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c > @@ -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? */ > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c > index b1645ad83a1e1..6c92f0fbeac98 100644 > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c > @@ -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; > -- > Sean Paul, Software Engineer, Google / Chromium OS >
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c index 0b9dc042d2e22..f197dce545761 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c @@ -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? */ diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c index b1645ad83a1e1..6c92f0fbeac98 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c @@ -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;