Messages in this thread | | | Date | Thu, 12 May 2022 00:27:02 +0300 | Subject | Re: [PATCH v3] drm/msm/dp: Always clear mask bits to disable interrupts at dp_ctrl_reset_irq_ctrl() | From | Dmitry Baryshkov <> |
| |
On 11/05/2022 23:04, Kuogee Hsieh wrote: > dp_catalog_ctrl_reset() will software reset DP controller. But it will > not reset programmable registers to default value. DP driver still have > to clear mask bits to interrupt status registers to disable interrupts > after software reset of controller. This patch removes the enable flag > condition checking to always clear mask bits of interrupt status > registers to disable interrupts if enable flag is false. > > This patch also will fix the potential problem happen at system suspend where > dp_ctrl_reset_irq_ctrl() was called to try to disable HPD related irqs but > the irq is still unmasked unexpectedly and can come in while system are > suspending. This leads to bus hangs if the irq is handled after we power down > the DP hardware because we run the irq handler and access a device register > assuming that no irq could ever come in if we powered down the device. We > don't know when the irq will be handled though, so it's possible the irq is > pending from before we disable the irq in the hardware. > > Changes in v2: > -- add more details commit text > > Changes in v3: > -- add synchrons_irq() > -- add atomic_t suspended > > Fixes: ba0a422be723 ("drm/msm/dp: do not initialize phy until plugin interrupt received")
Revision in the Fixes tag is incorrect
> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> > --- > drivers/gpu/drm/msm/dp/dp_ctrl.c | 9 +++++++-- > drivers/gpu/drm/msm/dp/dp_display.c | 18 ++++++++++++++++++ > 2 files changed, 25 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c > index af7a80c..f3e333e 100644 > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c > @@ -1389,8 +1389,13 @@ void dp_ctrl_reset_irq_ctrl(struct dp_ctrl *dp_ctrl, bool enable) > > dp_catalog_ctrl_reset(ctrl->catalog); > > - if (enable) > - dp_catalog_ctrl_enable_irq(ctrl->catalog, enable); > + /* > + * all dp controller programmable registers will not > + * be reset to default value after DP_SW_RESET > + * therefore interrupt mask bits have to be updated > + * to enable/disable interrupts > + */ > + dp_catalog_ctrl_enable_irq(ctrl->catalog, enable); > } > > void dp_ctrl_phy_init(struct dp_ctrl *dp_ctrl) > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c > index c388323..c34dbfc 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -98,6 +98,8 @@ struct dp_display_private { > struct dp_ctrl *ctrl; > struct dp_debug *debug; > > + atomic_t suspended; > + > struct dp_usbpd_cb usbpd_cb; > struct dp_display_mode dp_mode; > struct msm_dp dp_display; > @@ -187,6 +189,11 @@ static int dp_add_event(struct dp_display_private *dp_priv, u32 event, > int pndx; > > spin_lock_irqsave(&dp_priv->event_lock, flag); > + if (atomic_read(&dp_priv->suspended)) { > + spin_unlock_irqrestore(&dp_priv->event_lock, flag); > + return -EPERM; > + } > + > pndx = dp_priv->event_pndx + 1; > pndx %= DP_EVENT_Q_MAX; > if (pndx == dp_priv->event_gndx) { > @@ -454,6 +461,13 @@ static void dp_display_host_deinit(struct dp_display_private *dp) > dp->dp_display.connector_type, dp->core_initialized, > dp->phy_initialized); > > + if (!dp->core_initialized) { > + DRM_DEBUG_DP("DP core not initialized\n"); > + return; > + } > + > + synchronize_irq(dp->irq); > + > dp_ctrl_reset_irq_ctrl(dp->ctrl, false); > dp_aux_deinit(dp->aux); > dp_power_deinit(dp->power); > @@ -1362,6 +1376,8 @@ static int dp_pm_resume(struct device *dev) > dp->dp_display.connector_type, dp->core_initialized, > dp->phy_initialized, dp_display->power_on); > > + atomic_set(&dp->suspended, 0); > + > /* start from disconnected state */ > dp->hpd_state = ST_DISCONNECTED; > > @@ -1431,6 +1447,8 @@ static int dp_pm_suspend(struct device *dev) > dp->dp_display.connector_type, dp->core_initialized, > dp->phy_initialized, dp_display->power_on); > > + atomic_inc(&dp->suspended); > + > /* mainlink enabled */ > if (dp_power_clk_status(dp->power, DP_CTRL_PM)) > dp_ctrl_off_link_stream(dp->ctrl);
-- With best wishes Dmitry
| |