readding original poster
On Wed, 29 May 2024 at 09:57, Ben Skeggs <bskeggs@xxxxxxxxxx> wrote:
>
> On 29/5/24 07:52, Vasily Khoruzhick wrote:
>
> > If the card doesn't have display hardware, hpd_work and hpd_lock are
> > left uninitialized which causes BUG when attempting to schedule hpd_work
> > on runtime PM resume.
>
> Hi,
>
> Good catch, thank you for looking at this. A couple of initial comments
> below:
>
> Ben.
>
> >
> > Fix it by adding headless flag to DRM and skip any hpd if it's set.
> >
> > Fixes: ae1aadb1eb8d ("nouveau: don't fail driver load if no display hw present.")
> > Link: https://gitlab.freedesktop.org/drm/nouveau/-/issues/337
> > Signed-off-by: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/nouveau/dispnv04/disp.c | 2 +-
> > drivers/gpu/drm/nouveau/dispnv50/disp.c | 2 +-
> > drivers/gpu/drm/nouveau/nouveau_connector.c | 3 +++
> > drivers/gpu/drm/nouveau/nouveau_display.c | 11 ++++++++++-
> > drivers/gpu/drm/nouveau/nouveau_drv.h | 1 +
> > 5 files changed, 16 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/nouveau/dispnv04/disp.c b/drivers/gpu/drm/nouveau/dispnv04/disp.c
> > index 13705c5f1497..4b7497a8755c 100644
> > --- a/drivers/gpu/drm/nouveau/dispnv04/disp.c
> > +++ b/drivers/gpu/drm/nouveau/dispnv04/disp.c
> > @@ -68,7 +68,7 @@ nv04_display_fini(struct drm_device *dev, bool runtime, bool suspend)
> > if (nv_two_heads(dev))
> > NVWriteCRTC(dev, 1, NV_PCRTC_INTR_EN_0, 0);
> >
> > - if (!runtime)
> > + if (!runtime && !drm->headless)
> > cancel_work_sync(&drm->hpd_work);
> >
> > if (!suspend)
> > diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > index 88728a0b2c25..674dc567e179 100644
> > --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> > @@ -2680,7 +2680,7 @@ nv50_display_fini(struct drm_device *dev, bool runtime, bool suspend)
> > nv50_mstm_fini(nouveau_encoder(encoder));
> > }
> >
> > - if (!runtime)
> > + if (!runtime && !drm->headless)
> > cancel_work_sync(&drm->hpd_work);
> > }
> >
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
> > index 856b3ef5edb8..b315a2ef5b28 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_connector.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
> > @@ -1190,6 +1190,9 @@ nouveau_connector_hpd(struct nouveau_connector *nv_connector, u64 bits)
> > u32 mask = drm_connector_mask(&nv_connector->base);
> > unsigned long flags;
> >
> > + if (drm->headless)
> > + return;
> > +
>
> You shouldn't need this change, the function can't be called if there's
> no display.
>
>
> > spin_lock_irqsave(&drm->hpd_lock, flags);
> > if (!(drm->hpd_pending & mask)) {
> > nv_connector->hpd_pending |= bits;
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c
> > index aed5d5b51b43..1961ef665e97 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_display.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_display.c
> > @@ -450,6 +450,9 @@ nouveau_display_hpd_resume(struct drm_device *dev)
> > {
> > struct nouveau_drm *drm = nouveau_drm(dev);
> >
> > + if (drm->headless)
> > + return;
> > +
> > spin_lock_irq(&drm->hpd_lock);
> > drm->hpd_pending = ~0;
> > spin_unlock_irq(&drm->hpd_lock);
> > @@ -468,6 +471,11 @@ nouveau_display_hpd_work(struct work_struct *work)
> > int changed = 0;
> > struct drm_connector *first_changed_connector = NULL;
> >
> > + WARN_ON_ONCE(drm->headless);
> > +
> > + if (drm->headless)
> > + return;
> > +
>
> Same here.
>
>
> > pm_runtime_get_sync(dev->dev);
> >
> > spin_lock_irq(&drm->hpd_lock);
> > @@ -635,7 +643,7 @@ nouveau_display_fini(struct drm_device *dev, bool suspend, bool runtime)
> > }
> > drm_connector_list_iter_end(&conn_iter);
> >
> > - if (!runtime)
> > + if (!runtime && !drm->headless)
> > cancel_work_sync(&drm->hpd_work);
> >
> > drm_kms_helper_poll_disable(dev);
> > @@ -729,6 +737,7 @@ nouveau_display_create(struct drm_device *dev)
> > /* no display hw */
> > if (ret == -ENODEV) {
> > ret = 0;
> > + drm->headless = true;
> > goto disp_create_err;
> > }
> >
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
> > index e239c6bf4afa..25fca98a20bc 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_drv.h
> > +++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
> > @@ -276,6 +276,7 @@ struct nouveau_drm {
> > /* modesetting */
> > struct nvbios vbios;
> > struct nouveau_display *display;
> > + bool headless;
> > struct work_struct hpd_work;
> > spinlock_t hpd_lock;
> > u32 hpd_pending;
