On Tue, Mar 06, 2018 at 10:31:27AM +0100, Daniel Vetter wrote:
> On Tue, Feb 27, 2018 at 02:57:00PM +0200, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> >
> > edid and display_info are protected by mode_config.mutex. Add lockdep
> > asserts to make sure we're not accessing things w/o the lock.
> >
> > FIXME: pretty sure this will blow up with amdgpu as they seem
> > to be doing edid updates even from the modeset path. Need to figure
> > out what to do about that. Maybe protect the edid/display info with
> > with connection_mutex instead of mode_config.mutex?
>
> Imo not doing EDID udpates from the modeset path is the right fix. I can't
> think of any reasonable reason to do that at least. Can you point me at
> the relevant amdgpu code pls (I'm lazy, sry)?
It was some MST thing I believe... (should have written it down)
amdgpu_dm_atomic_check() -> dm_update_crtcs_state() ->
create_stream_for_sink() -> dm_dp_mst_dc_sink_create() ->
get_edid/update_edid_property
>
> Otherwise I think this is a real good patch.
>
> Thanks, Daniel
>
> >
> > Cc: Keith Packard <keithp@xxxxxxxxxx>
> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > Cc: Harry Wentland <harry.wentland@xxxxxxx>
> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/drm_connector.c | 4 ++++
> > drivers/gpu/drm/drm_edid.c | 2 ++
> > drivers/gpu/drm/drm_probe_helper.c | 2 +-
> > 3 files changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> > index 122060792b6f..a9f3536f4e94 100644
> > --- a/drivers/gpu/drm/drm_connector.c
> > +++ b/drivers/gpu/drm/drm_connector.c
> > @@ -1374,6 +1374,8 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
> > size_t size = 0;
> > int ret;
> >
> > + lockdep_assert_held(&dev->mode_config.mutex);
> > +
> > /* ignore requests to set edid when overridden */
> > if (connector->override_edid)
> > return 0;
> > @@ -1770,6 +1772,8 @@ void drm_connector_reset_display_info(struct drm_connector *connector)
> > {
> > struct drm_display_info *info = &connector->display_info;
> >
> > + lockdep_assert_held(&connector->dev->mode_config.mutex);
> > +
> > memset(info, 0, sizeof(*info));
> > }
> > EXPORT_SYMBOL_GPL(drm_connector_reset_display_info);
> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > index 618093c4a039..7f9e9236114b 100644
> > --- a/drivers/gpu/drm/drm_edid.c
> > +++ b/drivers/gpu/drm/drm_edid.c
> > @@ -4440,6 +4440,8 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
> > struct drm_display_info *info = &connector->display_info;
> > u32 quirks = edid_get_quirks(edid);
> >
> > + lockdep_assert_held(&connector->dev->mode_config.mutex);
> > +
> > info->width_mm = edid->width_cm * 10;
> > info->height_mm = edid->height_cm * 10;
> >
> > diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> > index 7dc7e635d7e4..2a2afcf72788 100644
> > --- a/drivers/gpu/drm/drm_probe_helper.c
> > +++ b/drivers/gpu/drm/drm_probe_helper.c
> > @@ -400,7 +400,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
> > enum drm_connector_status old_status;
> > struct drm_modeset_acquire_ctx ctx;
> >
> > - WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
> > + lockdep_assert_held(&dev->mode_config.mutex);
> >
> > drm_modeset_acquire_init(&ctx, 0);
> >
> > --
> > 2.13.6
> >
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
--
Ville Syrjälä
Intel OTC
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