Re: [PATCH] drm/bridge/synopsys: dw-hdmi: fix dw_hdmi_setup_rx_sense

[Sean Paul <seanpaul@chromium.org>]

On Wed, May 30, 2018 at 11:43:58AM +0200, Neil Armstrong wrote:
> The dw_hdmi_setup_rx_sense exported function should not use struct device
> to recover the dw-hdmi context using drvdata, but take struct dw_hdmi
> directly like other exported functions.
> 
> This caused a regression using Meson DRM on S905X since v4.17-rc1 :
> 
> Internal error: Oops: 96000007 [#1] PREEMPT SMP
> [...]
> CPU: 0 PID: 124 Comm: irq/32-dw_hdmi_ Not tainted 4.17.0-rc7 #2
> Hardware name: Libre Technology CC (DT)
> [...]
> pc : osq_lock+0x54/0x188
> lr : __mutex_lock.isra.0+0x74/0x530
> [...]
> Process irq/32-dw_hdmi_ (pid: 124, stack limit = 0x00000000adf418cb)
> Call trace:
>   osq_lock+0x54/0x188
>   __mutex_lock_slowpath+0x10/0x18
>   mutex_lock+0x30/0x38
>   __dw_hdmi_setup_rx_sense+0x28/0x98
>   dw_hdmi_setup_rx_sense+0x10/0x18
>   dw_hdmi_top_thread_irq+0x2c/0x50
>   irq_thread_fn+0x28/0x68
>   irq_thread+0x10c/0x1a0
>   kthread+0x128/0x130
>   ret_from_fork+0x10/0x18
>  Code: 34000964 d00050a2 51000484 9135c042 (f864d844)
>  ---[ end trace 945641e1fbbc07da ]---
>  note: irq/32-dw_hdmi_[124] exited with preempt_count 1
>  genirq: exiting task "irq/32-dw_hdmi_" (124) is an active IRQ thread (irq 32)
> 
> Fixes: eea034af90c6 ("drm/bridge/synopsys: dw-hdmi: don't clobber drvdata")
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> Tested-by: Koen Kooi <koen@dominion.thruhere.net>

Thanks for your patch, Neil. I've applied it to -misc-fixes and will send it to
Dave in hope it can sneak into 4.17.

Sean

> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 15 ++++-----------
>  drivers/gpu/drm/meson/meson_dw_hdmi.c     |  2 +-
>  include/drm/bridge/dw_hdmi.h              |  2 +-
>  3 files changed, 6 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index ec8d000..3c136f2b 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -2077,7 +2077,7 @@ static irqreturn_t dw_hdmi_hardirq(int irq, void *dev_id)
>  	return ret;
>  }
>  
> -void __dw_hdmi_setup_rx_sense(struct dw_hdmi *hdmi, bool hpd, bool rx_sense)
> +void dw_hdmi_setup_rx_sense(struct dw_hdmi *hdmi, bool hpd, bool rx_sense)
>  {
>  	mutex_lock(&hdmi->mutex);
>  
> @@ -2103,13 +2103,6 @@ void __dw_hdmi_setup_rx_sense(struct dw_hdmi *hdmi, bool hpd, bool rx_sense)
>  	}
>  	mutex_unlock(&hdmi->mutex);
>  }
> -
> -void dw_hdmi_setup_rx_sense(struct device *dev, bool hpd, bool rx_sense)
> -{
> -	struct dw_hdmi *hdmi = dev_get_drvdata(dev);
> -
> -	__dw_hdmi_setup_rx_sense(hdmi, hpd, rx_sense);
> -}
>  EXPORT_SYMBOL_GPL(dw_hdmi_setup_rx_sense);
>  
>  static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
> @@ -2145,9 +2138,9 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>  	 */
>  	if (intr_stat &
>  	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
> -		__dw_hdmi_setup_rx_sense(hdmi,
> -					 phy_stat & HDMI_PHY_HPD,
> -					 phy_stat & HDMI_PHY_RX_SENSE);
> +		dw_hdmi_setup_rx_sense(hdmi,
> +				       phy_stat & HDMI_PHY_HPD,
> +				       phy_stat & HDMI_PHY_RX_SENSE);
>  
>  		if ((phy_stat & (HDMI_PHY_RX_SENSE | HDMI_PHY_HPD)) == 0)
>  			cec_notifier_set_phys_addr(hdmi->cec_notifier,
> diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> index a393095..c9ad456 100644
> --- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
> @@ -529,7 +529,7 @@ static irqreturn_t dw_hdmi_top_thread_irq(int irq, void *dev_id)
>  		if (stat & HDMITX_TOP_INTR_HPD_RISE)
>  			hpd_connected = true;
>  
> -		dw_hdmi_setup_rx_sense(dw_hdmi->dev, hpd_connected,
> +		dw_hdmi_setup_rx_sense(dw_hdmi->hdmi, hpd_connected,
>  				       hpd_connected);
>  
>  		drm_helper_hpd_irq_event(dw_hdmi->encoder.dev);
> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
> index dd2a8cf..ccb5aa8 100644
> --- a/include/drm/bridge/dw_hdmi.h
> +++ b/include/drm/bridge/dw_hdmi.h
> @@ -151,7 +151,7 @@ struct dw_hdmi *dw_hdmi_bind(struct platform_device *pdev,
>  			     struct drm_encoder *encoder,
>  			     const struct dw_hdmi_plat_data *plat_data);
>  
> -void dw_hdmi_setup_rx_sense(struct device *dev, bool hpd, bool rx_sense);
> +void dw_hdmi_setup_rx_sense(struct dw_hdmi *hdmi, bool hpd, bool rx_sense);
>  
>  void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate);
>  void dw_hdmi_audio_enable(struct dw_hdmi *hdmi);
> -- 
> 2.7.4
> 
> 
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-- 
Sean Paul, Software Engineer, Google / Chromium OS